OFFSET
1,3
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
P. Moree, Convoluted convolved Fibonacci numbers
FORMULA
G.f.: (z/9)[1/(1-z-z^2)^9-1/(1-z^3-z^6)^3].
MAPLE
with(numtheory): f := z->1/(1-z-z^2): m := proc(r, j) d := divisors(r): W := (1/r)*z*sum(mobius(d[i])*f(z^d[i])^(r/d[i]), i=1..nops(d)): Wser := simplify(series(W, z=0, 80)): coeff(Wser, z^j) end: seq(m(9, j), j=1..40);
MATHEMATICA
CoefficientList[(z/9)(1/(1-z-z^2)^9 - 1/(1-z^3-z^6)^3) + O[z]^28, z] // Rest (* Jean-François Alcover, Dec 09 2017 *)
PROG
(PARI) concat(0, Vec(x^2*(1 - x)^2*(1 + x)^2*(1 - 3*x + 3*x^2 + 4*x^3 - 9*x^4 - 3*x^5 + 11*x^6 + 3*x^7 - 9*x^8 - 4*x^9 + 3*x^10 + 3*x^11 + x^12) / ((1 - x - x^2)^9*(1 - x^3 - x^6)^3) + O(x^40))) \\ Colin Barker, Dec 09 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 05 2003
EXTENSIONS
Edited by Emeric Deutsch, Mar 06 2004
STATUS
approved