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 A118737 #18 Aug 30 2021 19:33:17
%S A118737 0,1,2,1,5,6,7,9,7,8,13,11,15,17,16,15,18,20,18,26,21,20,27,27,26,40,
%T A118737 30,30,37,32,33,39,36,43,37,42,40,44,51,45,40,42,49,48,51,52,57,61,58,
%U A118737 54,59,59,67,60,68,54,70,66,61,72,79,65,70,66,63,73,67,71,76,72,80,86,78
%N A118737 Number of zeros in binary expansion of 5^n.
%H A118737 Robert Israel, <a href="/A118737/b118737.txt">Table of n, a(n) for n = 0..10000</a>
%F A118737 a(n) + A118738(n) = A061785(n)+1 for n >= 1. - _Robert Israel_, Dec 24 2017
%F A118737 a(n) = A023416(A000351(n)). - _Felix Fröhlich_, Dec 24 2017
%p A118737 seq(numboccur(0,convert(5^n,base,2)),n=0..100); # _Robert Israel_, Dec 24 2017
%t A118737 a[n_] := DigitCount[5^n, 2, 0]; Table[a[n], {n, 0, 72}] (* _Ray Chandler_, Sep 29 2006 *)
%t A118737 DigitCount[5^Range[0,80],2,0] (* _Harvey P. Dale_, Aug 30 2021 *)
%o A118737 (PARI) a(n) = #binary(5^n)-hammingweight(5^n) \\ _Felix Fröhlich_, Dec 24 2017
%Y A118737 Cf. A000351, A023416, A061785, A118738.
%K A118737 base,nonn
%O A118737 0,3
%A A118737 _Zak Seidov_, May 22 2006