A027636 Expansion of (1+x^19)/((1-x^2)*(1-x^4)^2*(1-x^6)).

1, 0, 1, 0, 3, 0, 4, 0, 7, 0, 9, 0, 14, 0, 17, 0, 24, 0, 29, 1, 38, 1, 45, 3, 57, 4, 66, 7, 81, 9, 93, 14, 111, 17, 126, 24, 148, 29, 166, 38, 192, 45, 214, 57, 244, 66, 270, 81, 305, 93, 335, 111, 375, 126, 410, 148, 455

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• B. Runge, On Siegel modular forms II, Nagoya Math. J., 138 (1995), 179-197.
• Index entries for linear recurrences with constant coefficients, signature (1,0,0,2,-2,1,-1,-1,1,-2,2,0,0,1,-1).

Crossrefs

Cf. A027640.

Programs

Magma

R:=PowerSeriesRing(Integers(), 70); Coefficients(R!( (1+x^19)/((1-x^2)*(1-x^4)^2*(1-x^6) ))); // G. C. Greubel, Aug 04 2022

Mathematica

CoefficientList[Series[(1+x^19)/((1-x^2)(1-x^4)^2(1-x^6)),{x,0,70}],x] (* Harvey P. Dale, Oct 13 2015 *)

SageMath

def A027636_list(prec):
    P. = PowerSeriesRing(ZZ, prec)
    return P( (1+x^19)/((1-x^2)*(1-x^4)^2*(1-x^6)) ).list()
A027636_list(70) # G. C. Greubel, Aug 04 2022

Formula

G.f.: (1+x^19)/((1-x^2) * (1-x^4)^2 * (1-x^6)).