Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #11 May 12 2020 12:49:34
%S 1,3,6,10,15,21,28,36,45,55,66,78,91,105,120,136,153,171,190,210,231,
%T 254,278,303,329,356,384,413,443,474,506,539,573,608,644,681,719,758,
%U 798,839,881,924,969,1015,1062,1110,1159,1209,1260,1312,1365,1419,1474,1530,1587
%N Index of 10^n within sequence of numbers of form 9^i*10^j.
%H Robert Israel, <a href="/A025747/b025747.txt">Table of n, a(n) for n = 0..2000</a>
%p N:= 10^60: # for a(0)..a(log[10](N))
%p L:= sort([seq(seq(9^i*10^j, j=0..ilog10(N/9^i)),i=0..floor(log[9](N)))]):
%p select(t -> L[t] mod 9 <> 0, [$1..nops(L)]); # _Robert Israel_, May 12 2020
%Y Cf. A022330.
%K nonn,easy
%O 0,2
%A _David W. Wilson_
%E Offset corrected by _Robert Israel_, May 12 2020