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 A092668 #11 Jan 22 2019 02:48:20 %S A092668 1,2,4,9,23,63,190,612,2056,7155,25482,92205,337594,1246863,4636390, %T A092668 17334801,65108062,245492244,928772650,3524337980,13409202676, %U A092668 51141124287,195470831356,748607855769,2872202028517,11038251159312 %N A092668 Bisection of A000011. %p A092668 with(numtheory): b:= proc(n) local s, d; if n = 0 then RETURN(1) else s := 2^(floor(n/2)); for d in divisors(n) do s := s+(phi(2*d)*2^(n/d))/(2*n); od; RETURN(s/2); fi; end: seq(b(2*n-1),n=1..30); # _Emeric Deutsch_, Feb 13 2006 %Y A092668 Cf. A000011, A000117. %K A092668 nonn,easy %O A092668 0,2 %A A092668 _N. J. A. Sloane_, Nov 24 2004 %E A092668 More terms from _Emeric Deutsch_, Feb 13 2006