1,3

R. J. Mathar, Table of n, a(n) for n = 1..1000

G. Martin, Dimensions of the spaces of cusp forms and newforms on Gamma_0(N) and Gamma_1(N), J. Numb. Theory 112 (2005) 298-331, Theorem 1

William A. Stein, Dimensions of the spaces S_k^{new}(Gamma_0(N))

William A. Stein, The modular forms database

Index entries for linear recurrences with constant coefficients, signature (0,1,1,0,-1).

G.f.: x^2*(1+3*x+x^2) / ( (1+x)*(1+x+x^2)*(x-1)^2 ). - R. J. Mathar, Jul 15 2015

Sequence in context: A020814 A286298 A128440 * A173258 A039858 A035558

Adjacent sequences: A063198 A063199 A063200 * A063202 A063203 A063204

nonn

N. J. A. Sloane, Jul 10 2001

approved