A092668 Bisection of A000011.

1, 2, 4, 9, 23, 63, 190, 612, 2056, 7155, 25482, 92205, 337594, 1246863, 4636390, 17334801, 65108062, 245492244, 928772650, 3524337980, 13409202676, 51141124287, 195470831356, 748607855769, 2872202028517, 11038251159312

Offset: 0

Author

N. J. A. Sloane, Nov 24 2004

Keywords

• nonn
• easy

Crossrefs

Cf. A000011, A000117.

Programs

Maple

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

Extensions

More terms from Emeric Deutsch, Feb 13 2006