OFFSET
1,1
COMMENTS
The terms obey a(n)=10*(n-1)-a(n-1), n>2 as far as tabulated, [Vincenzo Librandi, Dec 07 2010, corrected by R. J. Mathar, Dec 07 2010]
LINKS
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 (1,1,-1).
FORMULA
From Colin Barker, Oct 16 2014: (Start)
a(n) = -5/2-(-1)^n/2+5*n for n>1.
a(n) = a(n-1)+a(n-2)-a(n-3) for n>4.
G.f.: -x*(x^3-4*x^2-5*x-2) / ((x-1)^2*(x+1)).
(End)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 10 2001
STATUS
approved