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 A097413 #15 Feb 16 2025 08:32:54
%S A097413 1,5,1,2,1,1,4,1,3,1,2,5,1,2,3,6,1,1,3,5,7,1,1,2,3,5,7,1,1,1,2,3,4,6,
%T A097413 7,1,1,1,2,2,3,4,5,6,7,9,1,1,1,1,2,2,3,3,4,5,6,7,8,1,1,1,1,1,2,2,2,3,
%U A097413 3,4,4,5,5,6,7,8,9,1,1,1,1,1,1,2,2,2,2,3,3,3,4,4,5,5,6,6,7,8,9,1,1,1,1
%N A097413 Initial decimal digit of n^9.
%H A097413 Robert Israel, <a href="/A097413/b097413.txt">Table of n, a(n) for n = 1..10000</a>
%H A097413 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GelfandsQuestion.html">Gelfand's Question</a>
%F A097413 a(n) = A000030(n^9) = floor(n^9/10^A004216(n^9)). - _Robert Israel_, Jan 28 2016
%e A097413 1, 512, 19683, 262144, 1953125, 10077696, 40353607, 134217728, 387420489, 1000000000, ...
%p A097413 idd:= n -> floor(n/10^ilog10(n)):
%p A097413 seq(idd(n^9),n=2..100); # _Robert Israel_, Jan 28 2016
%t A097413 Table[IntegerDigits[n^9][[1]],{n,120}] (* _Harvey P. Dale_, Aug 25 2023 *)
%Y A097413 Cf. A000027, A000030, A002993, A002994, A004216, A097408, A097409, A097410, A097411, A097412, A097414.
%K A097413 nonn,base,easy
%O A097413 1,2
%A A097413 _Eric W. Weisstein_, Aug 16 2004