0,3

G.f.: 1/(1-x) + Sum_{n>1} x^n/(1-Sum_{d | 1<=d<=n, gcd(n,d)=1} x^d)^2.

A130709 := proc(n) local gf, den, i, d ; gf := 0 ; for i from 2 to n do den := 1 ; for d from 1 to i-1 do if gcd(d, i) = 1 then den := den-x^d ; fi ; od ; gf := taylor(gf+x^i/den^2, x=0, n+1) ; od: 1+coeftayl(gf, x=0, n) ; end: seq(A130709(n), n=0..40) ; # R. J. Mathar, Oct 28 2007

Sequence in context: A372782 A001036 A054150 * A051013 A128609 A335471

Adjacent sequences: A130706 A130707 A130708 * A130710 A130711 A130712

easy,nonn

Vladeta Jovovic, Jul 01 2007

More terms from R. J. Mathar, Oct 28 2007

approved