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 A145256 #11 Feb 06 2020 01:04:08
%S A145256 4,6,8,10,9,14,16,12,12,22,18,26,21,27,32,34,20,38,24,28,26,46,33,35,
%T A145256 28,30,35,58,39,62,64,36,36,42,40,74,42,45,48,82,44,86,50,51,54,94,66,
%U A145256 56,52,54,56,106,57,110,70,60,60,118,75,122,93,111,128,80,68,134,72,81,74
%N A145256 a(n) = the smallest integer > n that is non-coprime to n and has the same number of 1's in its binary representation as n has.
%C A145256 a(n) <= 2n since 2n is trivially a multiple of n and multiplying a number by 2 adds a 0 in base 2. - _Stefan Steinerberger_, Oct 17 2008
%H A145256 Rémy Sigrist, <a href="/A145256/b145256.txt">Table of n, a(n) for n = 2..65536</a>
%t A145256 a[n_] := Block[{}, i = n + 1; While[GCD[i, n] == 1 || Not[DigitCount[n, 2, 1] == DigitCount[i, 2, 1]], i++ ]; i]; Table[a[n], {n, 2, 100}] (* _Stefan Steinerberger_, Oct 17 2008 *)
%o A145256 (PARI) a(n) = for (m=n+1, oo, if (gcd(m,n)>1 && hammingweight(m)==hammingweight(n), return (m))) \\ _Rémy Sigrist_, Feb 06 2020
%Y A145256 Cf. A145254, A145255, A145257.
%K A145256 base,nonn
%O A145256 2,1
%A A145256 _Leroy Quet_, Oct 05 2008
%E A145256 Edited and corrected by _Stefan Steinerberger_, Oct 17 2008