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 A045674 #15 Sep 30 2017 14:55:05
%S A045674 1,1,2,2,4,4,6,8,12,16,20,32,38,64,72,128,140,256,272,512,532,1024,
%T A045674 1056,2048,2086,4096,4160,8192,8264,16384,16512,32768,32908,65536,
%U A045674 65792,131072,131344,262144,262656,524288,524820,1048576,1049600
%N A045674 Number of 2n-bead balanced binary necklaces which are equivalent to their reverse, complement and reversed complement.
%H A045674 Andrew Howroyd, <a href="/A045674/b045674.txt">Table of n, a(n) for n = 0..200</a>
%H A045674 <a href="/index/Ne#necklaces">Index entries for sequences related to necklaces</a>
%F A045674 a(2n) = a(n) + 2^(n-1), a(2n+1) = 2^n. - _Ralf Stephan_, Nov 01 2003
%t A045674 a[0] = 1; a[n_] := a[n] = If[EvenQ[n], 2^(n/2-1) + a[n/2], 2^((n-1)/2)]; Table[a[n], {n, 0, 42}] (* _Jean-François Alcover_, Sep 30 2017 *)
%o A045674 (PARI) a(n) = if(n<1, n==0, my(t=0,r=n); while(r%2==0, r=r/2; t+=2^(r-1)); t + 2^(r\2)); \\ _Andrew Howroyd_, Sep 29 2017
%Y A045674 Cf. A045654.
%K A045674 nonn
%O A045674 0,3
%A A045674 _David W. Wilson_