{"id":251,"date":"2026-08-29T17:30:17","date_gmt":"2026-08-29T17:30:17","guid":{"rendered":"https:\/\/mathrelated.co.uk\/?p=251"},"modified":"2026-08-29T17:32:15","modified_gmt":"2026-08-29T17:32:15","slug":"element-5-and-set-1-15t5t","status":"publish","type":"post","link":"https:\/\/mathrelated.co.uk\/index.php\/2026\/08\/29\/element-5-and-set-1-15t5t\/","title":{"rendered":"Element 5 and set 1+(-1+5^t)*(5^t)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Consider the space<\/p>\n\n\n\n<div class=\"wp-block-math\"><math display=\"block\"><semantics><mrow><mn>1<\/mn><mo>+<\/mo><mo form=\"prefix\" stretchy=\"false\">(<\/mo><mo form=\"prefix\" stretchy=\"false\">\u2212<\/mo><mn>1<\/mn><mo>+<\/mo><msup><mn>5<\/mn><mi>t<\/mi><\/msup><mo form=\"postfix\" stretchy=\"false\">)<\/mo><mo>\u2217<\/mo><mo form=\"prefix\" stretchy=\"false\">(<\/mo><msup><mn>5<\/mn><mi>t<\/mi><\/msup><mo form=\"postfix\" stretchy=\"false\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">1+(-1+5^t)*(5^{t})<\/annotation><\/semantics><\/math><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">We will be using generating element 5<br><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The groups generated by 5 have low order [ a lot lower than n-1 ]<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tabulating the elements of groups generated by 5 next<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Using prefix NNd to avoid clashing with existing letter conventions for groups.<br>Prefer G or S? Replace them in your local copy.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Conjecture<\/strong>: Order of 5 mod N when N of the form 1+(-1+5^t)*(5^t) is 6\u00d7t<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When t=2 we have P=1+24\u00d725 and the set of elements modulo P is a multiplicative group.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><br>The multiplicative group generated by 5 has 12 elements<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><br>The elements in <strong>NNd12<\/strong> are<br>   { 5, 25, 125, 24, 120, <strong>-1<\/strong>, 596, 576, 476, 577, 481, 1 }<br><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If <strong>NNd12<\/strong> is really a group then we need inverses so let us document those next.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Inverse of 5 is 481 mod P<\/li>\n\n\n\n<li>Inverse of 25 is 577 mod P<\/li>\n\n\n\n<li>Inverse of 125 is 476 mod P<\/li>\n\n\n\n<li>Inverse of 24 is 576 mod P<\/li>\n\n\n\n<li>Inverse of 120 is 596 mod P<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">We could alternatively write the group <strong>NNd12<\/strong> as follows:<br>   { 5, 25, 125, (5^4), (5^5), -1,<br>   -5, -25, -125, -(5^4), -(5^5), 1, }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For 15501 from t=3 the 18 elements in <strong>NNd18<\/strong> are as shown next<br>   { 5, 25, 125, 625, 3125, 124, 620, 3100, <strong>-1<\/strong>,<br>   15496, 15476, 15376, 14876, 12376, 15377, 14881, 12401, 1 }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For 390001 from t=4 the 24 elements in <strong>NNd24<\/strong> are as shown next<br>   { 5, 25, 125, 625, 3125, 15625, 78125, 624,<br>   3120, 15600, 78000, <strong>-1<\/strong>, 389996, 389976, 389876, 389376,<br>   386876, 374376, 311876, 389377, 386881, 374401, 312001, 1 }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For 9762501 from t=5 the 30 elements in <strong>NNd30<\/strong> are as shown next<br>   { 5, 25, 125, 625, 3125, 15625,<br>   78125, 390625, 1953125, 3124, 15620, 78100,<br>   390500, 1952500, <strong>-1<\/strong>, 9762496, 9762476, 9762376,<br>   9761876, 9759376, 9746876, 9684376, 9371876, 7809376,<br>   9759377, 9746881, 9684401, 9372001, 7810001, 1 }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For 244125001 from t=6 the 36 elements in <strong>NNd36<\/strong> are as shown next<br>   { 5, 25, 125, 625, 3125, 15625,<br>   78125, 390625, 1953125, 9765625, 48828125, 15624,<br>   78120, 390600, 1953000, 9765000, 48825000, <strong>-1<\/strong>,<br>   244124996, 244124976, 244124876,<br>   244124376, 244121876, 244109376,<br>   244046876, 243734376, 242171876,<br>   234359376, 195296876, 244109377,<br>   244046881, 243734401, 242172001,<br>   234360001, 195300001, 1 }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For 6103437501 from t=7 the 42 elements in <strong>NNd42<\/strong> are as shown next<br>{ 5, 25, 125, 625, 3125, 15625,<br>78125, 390625, 1953125, 9765625, 48828125, 244140625,<br>1220703125, 78124, 390620, 1953100, 9765500, 48827500,<br>244137500, 1220687500, <strong>-1<\/strong>,<br>6103437496, 6103437476, 6103437376,<br>6103436876, 6103434376, 6103421876,<br>6103359376, 6103046876, 6101484376,<br>6093671876, 6054609376, 5859296876,<br>4882734376, 6103359377, 6103046881,<br>6101484401, 6093672001, 6054610001,<br>5859300001, 4882750001, 1 }<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For t=8 the 48 elements in <strong>NNd48<\/strong> are not tabulated here<br>For t=9 the 54 elements in <strong>NNd54<\/strong> are not tabulated here<br>For t=10 the 60 elements in <strong>NNd60<\/strong> are not tabulated here<br>For t=11 the 66 elements in <strong>NNd66<\/strong> are not tabulated here<br>For t=12 the 72 elements in <strong>NNd72<\/strong> are not tabulated here<br>For t=13 the 78 elements in <strong>NNd78<\/strong> are not tabulated here<br>For t=14 the 84 elements in <strong>NNd84<\/strong> are not tabulated here<br>For t=15 the 90 elements in <strong>NNd90<\/strong> are not tabulated here<br>For t=16 the 96 elements in <strong>NNd96<\/strong> are not tabulated here<br>For t=17 the 102 elements in <strong>NNd102<\/strong> are not tabulated here<br>For t=18 the 108 elements in <strong>NNd108<\/strong> are not tabulated here<br>For t=19 the 114 elements in <strong>NNd114<\/strong> are not tabulated here<br>For t=20 the 120 elements in <strong>NNd120<\/strong> are not tabulated here<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Using sturdy element notation we might say the results tabulated in this post are<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"756\" height=\"85\" src=\"https:\/\/mathrelated.co.uk\/wp-content\/uploads\/2026\/08\/sturdyelementnotation5forMinus5times5toT.png\" alt=\"sturdy element notation for element 5 in enclosing set 1+(-1+5^t)*(5^t)\" class=\"wp-image-252\" srcset=\"https:\/\/mathrelated.co.uk\/wp-content\/uploads\/2026\/08\/sturdyelementnotation5forMinus5times5toT.png 756w, https:\/\/mathrelated.co.uk\/wp-content\/uploads\/2026\/08\/sturdyelementnotation5forMinus5times5toT-300x34.png 300w\" sizes=\"auto, (max-width: 756px) 100vw, 756px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Consider the space We will be using generating element 5 The groups generated by 5 have low order [ a lot lower than n-1 ] Tabulating the elements of groups generated by 5 next Using prefix NNd to avoid clashing with existing letter conventions for groups.Prefer G or S? Replace them in your local copy. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,5],"tags":[7,8],"class_list":["post-251","post","type-post","status-publish","format-standard","hentry","category-abstractalgebra","category-mathematics","tag-cyclic","tag-group"],"_links":{"self":[{"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/251","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=251"}],"version-history":[{"count":1,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/251\/revisions"}],"predecessor-version":[{"id":253,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/251\/revisions\/253"}],"wp:attachment":[{"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=251"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mathrelated.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}