OFFSET
1,3
COMMENTS
LINKS
P. Moree, Convoluted convolved Fibonacci numbers
Pieter Moree, The formal series Witt transform, Discr. Math. no. 295 vol. 1-3 (2005) 143-160.
FORMULA
G.f.: (z/6)[1/(1-z-z^2)^6-1/(1-z^2-z^4)^3-1/(1-z^3-z^6)^2+1/(1-z^6-z^12)].
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(6, j), j=1..40);
MATHEMATICA
f[k_] = 1/(1 - z^k - z^(2k))^(6/k); (1/6) (f[1] - f[2] - f[3] + f[6]) + O[z]^30 // CoefficientList[#, z]& (* Jean-François Alcover, Mar 24 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 05 2003
EXTENSIONS
Edited by Emeric Deutsch, Mar 06 2004
STATUS
approved