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 A014886 #6 Mar 30 2012 17:28:13
%S A014886 679922,679923,679924,679925,679926,679927,679928,679929,1048576,
%T A014886 16777216,17457138,17457139,17457140,17457141,17457142,17457143,
%U A014886 17457144,17457145,17825792
%N A014886 n is equal to the number of 2's in all numbers <= n written in base 8.
%o A014886 (Perl) ($s,$t,$u)=(0,'1',1); while($s <= $u*8){print "$u " if $s == $u; ($p,$o)=
%o A014886 (Perl) (1,0); $q=($t =~ /^(7*)/ && length $1); $r=length($t)+1; ++$o, $p *= 8 while
%o A014886 (Perl) $o+1 <= $q && $p*$r*8 <= abs($u-$s); $u += $p; s/^(7*)(.)?/(0 x length($1))
%o A014886 (Perl) .($2+1)/e, $s += tr/2/2/*$p + $o*$p/8 for substr $t,$o } print "\n"
%Y A014886 Cf. A014778.
%K A014886 nonn,base,fini,full
%O A014886 1,1
%A A014886 _Olivier Gérard_
%E A014886 More terms and Perl program from _Hugo van der Sanden_
%E A014886 Comment from Hugo van der Sanden: Program terminates at n = 2.94239143846251e+56, when 2.37843307942386e+57 2's have been seen; since s > 8n and n > 8^8 at this point, it is not possible for n ever again to catch up with the sum (given s(8^n) = n 8^{n-1}).