This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A054869 #34 Dec 05 2022 21:40:33 %S A054869 3,1,2,0,5,3,1,2,2,2,5,1,5,5,1,4,1,3,1,2,5,5,5,0,5,2,5,5,5,3,1,4,3,3, %T A054869 0,4,2,2,4,0,1,3,3,1,4,0,2,0,1,2,5,2,4,0,2,3,3,0,3,4,5,5,2,5,5,4,3,2, %U A054869 3,1,5,4,5,4,0,1,1,0,4,2,0,1,3,0,1,5,0,4,3,5,0,1,0,2,4,0,3,4,2 %N A054869 Digits of an idempotent 6-adic number. %C A054869 ( a(0) + a(1)*6 + a(2)*6^2 + ... )^k = a(0) + a(1)*6 + a(2)*6^2 + ... for each k. Apart from 0 and 1, in base 6 there are only 2 numbers with this property. For the other see A055620. %D A054869 V. deGuerre and R. A. Fairbairn, Automorphic numbers, J. Rec. Math., 1 (No. 3, 1968), 173-179. %H A054869 Kenny Lau, <a href="/A054869/b054869.txt">Table of n, a(n) for n = 0..9999</a> %H A054869 V. deGuerre and R. A. Fairbairn, <a href="/A003226/a003226.pdf">Automorphic numbers</a>, Jnl. Rec. Math., 1 (No. 3, 1968), 173-179 %F A054869 a(n) == 3^(2^n) (mod 6^n). - _Robert Dawson_, Oct 28 2022 %o A054869 (Python) %o A054869 n=10000;res=1-pow((3**n+1)//2,n,3**n)*2**n %o A054869 for i in range(n):print(i,res%6);res//=6 %o A054869 # _Kenny Lau_, Jun 09 2018 %Y A054869 The six examples given by deGuerre and Fairbairn are A055620, A054869, A018247, A018248, A259468, A259469. %K A054869 nonn,base %O A054869 0,1 %A A054869 Paolo Dominici (pl.dm(AT)libero.it), May 23 2000