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 A165820 #17 Mar 03 2018 09:48:00
%S A165820 1,4,19,16,89,100,113,64,593,1380,377,400,425,452,481,256,4385,1298,
%T A165820 723,10640,5561,11748,8471,18456,1649,1700,729,1808,1865,1924,1985,
%U A165820 1024,33857,9250,36041,75024,5477,11558,40433,83520,1681,87780,22329,92048
%N A165820 a(n) = the smallest positive integer that, when written in binary, contains both binary n and binary n^2 as substrings.
%H A165820 Rémy Sigrist, <a href="/A165820/b165820.txt">Table of n, a(n) for n = 1..10000</a>
%F A165820 a(n) = A294977(n, n^2). - _Rémy Sigrist_, Mar 03 2018
%t A165820 f[n_] := Block[{k = 1, is = IntegerString[n, 2], iss = IntegerString[n^2, 2]}, While[ StringPosition[ IntegerString[k, 2], is] == {} || StringPosition[ IntegerString[k, 2], iss] == {}, k++ ]; k]; Array[f, 44] (* _Robert G. Wilson v_, Oct 02 2009 *)
%Y A165820 Cf. A007088, A001737.
%Y A165820 Cf. A165819, A165821, A165822, A294977.
%K A165820 base,nonn
%O A165820 1,2
%A A165820 _Leroy Quet_, Sep 28 2009
%E A165820 a(7)-a(44) from _Robert G. Wilson v_, Oct 02 2009