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 A180699 #12 Oct 05 2019 04:54:04
%S A180699 1,256,309485009821345068724781056,4096,
%T A180699 5192296858534827628530496329220096,65536,72057594037927936,
%U A180699 83076749736557242056487941267521536,91343852333181432387730302044767688728495783936,1048576
%N A180699 Smallest power of 16 that begins with n.
%t A180699 Join[{1},Flatten[Table[Select[16^Range[50],Take[IntegerDigits[#], IntegerLength[ n]] == IntegerDigits[n]&,1],{n,0,20}]]] (* _Harvey P. Dale_, Feb 21 2013 *)
%Y A180699 Cf. A001025, A180697, A180700, A180701.
%K A180699 nonn,base
%O A180699 1,2
%A A180699 _Daniel Mondot_, Sep 18 2010
%E A180699 More terms from _Harvey P. Dale_, Feb 21 2013