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 A064854 #12 Dec 30 2024 12:51:39
%S A064854 1,0,7,0,21,37,118,56,19,428,808,3920,2256,15240,28312,46733,128931,
%T A064854 251439,434788,645833,1397733,1179155,7185704,1551886,33308648,
%U A064854 65879944,121274199,65829274,228529703,248939750,799831532,2835988891,1358930753,9419331043,9093076436
%N A064854 a(n) = ((5^n mod 4^n) mod 3^n) mod 2^n.
%C A064854 A generalization of A002380 and A064536. It arises also as a coefficient (=c1) of 1^n=1 in a special (greedy) decomposition of 5^n into like powers as follows: 5^n = c4*4^n + c3*3^n + c2*2^n + c1*1^n.
%H A064854 Harry J. Smith, <a href="/A064854/b064854.txt">Table of n, a(n) for n = 1..200</a>
%F A064854 n = 7: 5^7 = 78125 = 4*16384 + 5*2187 + 12*128 + 118*1, where a(7)=118, the last coefficient.
%o A064854 (PARI) a(n) = { ((5^n%4^n)%3^n)%2^n } \\ _Harry J. Smith_, Sep 28 2009
%Y A064854 Cf. A002380, A064536, A064855, A060692, A064628-A064631.
%K A064854 nonn
%O A064854 1,3
%A A064854 _Labos Elemer_, Oct 08 2001