OFFSET
1,1
LINKS
William A. Stein, Dimensions of the spaces S_k(Gamma_0(N)).
William A. Stein, The modular forms database
FORMULA
Conjectures from Colin Barker, Jun 09 2019: (Start)
G.f.: x*(3 + 9*x + 5*x^2 + x^3) / ((1 - x)^2*(1 + x)).
a(n) = a(n-1) + a(n-2) - a(n-3) for n>4.
a(n) = ((-1)^n + 18*n - 13)/2 for n>1.
(End)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 08 2001
STATUS
approved