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 A025708 #10 Jul 06 2025 13:05:07 %S A025708 1,2,4,7,11,16,21,27,34,42,51,61,71,82,94,107,121,136,151,167,184,202, %T A025708 221,241,261,282,304,327,351,375,400,426,453,481,510,539,569,600,632, %U A025708 665,699,733,768,804,841,879,918,957,997,1038,1080,1123,1167,1211,1256,1302 %N A025708 Index of 5^n within sequence of numbers of form 5^i*7^j. %C A025708 Position of zeros in A025667.- _R. J. Mathar_, Jul 06 2025 %H A025708 Charles R Greathouse IV, <a href="/A025708/b025708.txt">Table of n, a(n) for n = 0..10000</a> %o A025708 (PARI) a(n)=my(N=1); n+1+sum(i=1, n, logint(N*=5, 7)); \\ _Charles R Greathouse IV_, Jan 11 2018 %o A025708 (PARI) first(n)=my(s, N=1/5); vector(n+1, i, s+=logint(N*=5, 7)+1) \\ _Charles R Greathouse IV_, Jan 11 2018 %K A025708 nonn %O A025708 0,2 %A A025708 _David W. Wilson_ %E A025708 Offset corrected by _Charles R Greathouse IV_, Jan 11 2018