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 A088156 #5 Feb 16 2025 08:32:51 %S A088156 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,8,4,19,4,17,3,7,6,11,5,3, %T A088156 6,5,13,8,15,19,4,16,2,12,5,5,9,6,5,9,17,1,14,11,10,15,15,13,2,8,9,1, %U A088156 18,3,15,15,17,10,1,5,0,3,16,4,17,14,12,12,6,5,8,16,8,3,6,12,19,2,14 %N A088156 Value of n-th digit in vigesimal representation of n^n. %C A088156 a(n)=d(n) with n^n = Sum(d(k)*20^k: 0<=d(k)<20, k>=0). %H A088156 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Vigesimal.html">Vigesimal</a> %F A088156 a(n) = floor(n^n / 20^n) mod 20. %e A088156 n=30, 30^30=205891132094649*10^30 -> [93B83A81A7CBBA03C2241239C3C4840000000], a(30)=8. %e A088156 a(0)=1, a(k)=0 for 0<k<20 and a(20)=1. %Y A088156 Cf. A000312, A088150, A088151, A088152, A088153, A088154, A088155, A088157. %K A088156 nonn,base %O A088156 0,22 %A A088156 _Reinhard Zumkeller_, Sep 20 2003