A063122 - OEIS

%I #21 Apr 18 2023 21:51:02

%S 4,21,39,57,75,93,111,129,147,165,183,201,219,237,255,273,291,309,327,

%T 345,363,381,399,417,435,453,471,489,507,525,543,561,579,597,615,633,

%U 651,669,687,705,723,741,759,777,795,813,831,849,867,885

%N Dimension of the space of weight 2n cusp forms for Gamma_0( 54 ).

%C a(n) appears to be 18n-15, for n>1. - _Ralf Stephan_, Nov 13 2001.

%H William A. Stein, <a href="http://wstein.org/Tables/dimskg0n.gp">Dimensions of the spaces S_k(Gamma_0(N))</a>.

%H William A. Stein, <a href="http://wstein.org/Tables/">The modular forms database</a>

%F Conjectures from _Colin Barker_, Jun 10 2019: (Start)

%F G.f.: x*(4 + 13*x + x^2) / (1 - x)^2.

%F a(n) = 2*a(n-1) - a(n-2) for n>3.

%F (End)

%Y See A298035 for a very similar sequence.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Jul 08 2001