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 A048726 #14 Jun 30 2022 08:38:09
%S A048726 0,6,12,10,24,30,20,18,48,54,60,58,40,46,36,34,96,102,108,106,120,126,
%T A048726 116,114,80,86,92,90,72,78,68,66,192,198,204,202,216,222,212,210,240,
%U A048726 246,252,250,232,238,228,226,160,166,172,170,184,190,180,178,144,150
%N A048726 a(n) = Xmult(n,6), or 2*A048724(n).
%t A048726 Table[ BitXor[4n, 2n], {n, 0, 60}] (* _Robert G. Wilson v_, Jul 06 2006 *)
%o A048726 (PARI) a(n)=bitxor(2*n, 4*n) \\ _Charles R Greathouse IV_, Oct 03 2016
%o A048726 (Python)
%o A048726 def A048726(n): return (n^ n<<1)<<1 # _Chai Wah Wu_, Jun 29 2022
%Y A048726 Cf. A048720, A048724.
%K A048726 nonn,easy
%O A048726 0,2
%A A048726 _Antti Karttunen_, Apr 26 1999