OFFSET
0,3
FORMULA
G.f.: 1/(1-x) + Sum_{n>1} x^n/(1-Sum_{d | 1<=d<=n, gcd(n,d)=1} x^d)^2.
MAPLE
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
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Jul 01 2007
EXTENSIONS
More terms from R. J. Mathar, Oct 28 2007
STATUS
approved