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 A025747 #13 Jul 06 2025 13:21:06 %S A025747 1,3,6,10,15,21,28,36,45,55,66,78,91,105,120,136,153,171,190,210,231, %T A025747 254,278,303,329,356,384,413,443,474,506,539,573,608,644,681,719,758, %U A025747 798,839,881,924,969,1015,1062,1110,1159,1209,1260,1312,1365,1419,1474,1530,1587 %N A025747 Index of 10^n within sequence of numbers of form 9^i*10^j. %C A025747 Positions of zeros in A025683. - _R. J. Mathar_, Jul 06 2025 %H A025747 Robert Israel, <a href="/A025747/b025747.txt">Table of n, a(n) for n = 0..2000</a> %p A025747 N:= 10^60: # for a(0)..a(log[10](N)) %p A025747 L:= sort([seq(seq(9^i*10^j, j=0..ilog10(N/9^i)),i=0..floor(log[9](N)))]): %p A025747 select(t -> L[t] mod 9 <> 0, [$1..nops(L)]); # _Robert Israel_, May 12 2020 %Y A025747 Cf. A025635, A022330. %K A025747 nonn,easy %O A025747 0,2 %A A025747 _David W. Wilson_ %E A025747 Offset corrected by _Robert Israel_, May 12 2020