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 A145254 #13 Oct 27 2017 20:52:08
%S A145254 2,3,2,5,3,7,2,3,5,11,3,13,7,15,2,17,3,19,5,7,11,23,3,25,13,15,7,29,
%T A145254 15,31,2,3,6,7,3,37,14,15,5,41,7,43,11,15,23,47,3,7,14,15,13,53,15,55,
%U A145254 7,15,29,59,15,61,31,63,2,5,3,67,6,21,7,71,3,73,14,15,14,77,15,79,5,21,14,83
%N A145254 a(n) = the smallest positive integer that is non-coprime to n and has the same number of 1's in its binary representation as n.
%H A145254 Michael De Vlieger, <a href="/A145254/b145254.txt">Table of n, a(n) for n = 2..16384</a>
%t A145254 Table[Function[k, SelectFirst[Range[2, n], And[! CoprimeQ[#, n], DigitCount[#, 2, 1] == k] &]]@ DigitCount[n, 2, 1], {n, 2, 83}] (* _Michael De Vlieger_, Oct 26 2017 *)
%o A145254 (PARI) a(n) = {my(k = 1, hn = hammingweight(n)); while ((hammingweight(k) != hn) || (gcd(n, k) == 1), k++); k;} \\ _Michel Marcus_, Oct 27 2017
%Y A145254 Cf. A145255, A145256, A145257.
%K A145254 base,nonn,look
%O A145254 2,1
%A A145254 _Leroy Quet_, Oct 05 2008
%E A145254 Extended by _Ray Chandler_, Nov 03 2008