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 A138973 #25 Jun 24 2025 10:02:47 %S A138973 0,1,15,169,1695,15961,26846,450066,5247614,13156907,226316077, %T A138973 680627620,13354327932,65310761853,328708074010,1951441519231, %U A138973 15611532153848,158125187800385,101848932467045,7328445851378156,35829776440278962,286638211522231696 %N A138973 a(n) = 8^n mod 7^n. %H A138973 Seiichi Manyama, <a href="/A138973/b138973.txt">Table of n, a(n) for n = 0..1183</a> %t A138973 a[n_]:=PowerMod[8,n,7^n];Array[a,22,0] (* _James C. McMahon_, Jun 23 2025 *) %o A138973 (Sage) [power_mod(8,n,7^n) for n in range(0,22)] # _Zerinvary Lajos_, Nov 28 2009 %o A138973 (PARI) a(n) = lift(Mod(8, 7^n)^n); \\ _Michel Marcus_, Feb 20 2018 %Y A138973 Cf. k^n mod (k-1)^n: A002380 (k=3), A064629 (k=4), A138589 (k=5), A138649 (k=6), A139786 (k=7), this sequence (k=8), A139733 (k=9). %Y A138973 Cf. A000420, A001018. %K A138973 nonn %O A138973 0,3 %A A138973 _N. J. A. Sloane_, May 20 2008