OFFSET
0,2
COMMENTS
First denominator is 1, rest are 691.
REFERENCES
R. C. Gunning, Lectures on Modular Forms. Princeton Univ. Press, Princeton, NJ, 1962, p. 53.
N. Koblitz, Introduction to Elliptic Curves and Modular Forms, Springer-Verlag, 1984, see p. 111.
J.-P. Serre, Course in Arithmetic, Chap. VII, Section 4.
LINKS
Andy Huchala, Table of n, a(n) for n = 0..20000
H. D. Nguyen, D. Taggart, Mining the OEIS: Ten Experimental Conjectures, 2013; Mentions this sequence. - From N. J. A. Sloane, Mar 16 2014
MAPLE
with(numtheory):
E := proc(k) local n, t1; t1 := 1-(2*k/bernoulli(k))*add(sigma[k-1](n)*q^n, n=1..60); series(t1, q, 60); end; E(12);
seq(numer(coeff(%, q, n)), n=0..24);
MATHEMATICA
terms = 13; E12[x_] = 1 - (24/BernoulliB[12])*Sum[k^11*x^k/(1 - x^k), {k, 1, terms}]; E12[x] + O[x]^terms // CoefficientList[#, x]& // Numerator (* Jean-François Alcover, Feb 27 2018 *)
PROG
(Sage)
l = list(eisenstein_series_qexp(12, 20, normalization='integral'))
l[0] = 1; l # Andy Huchala, Jul 01 2021
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
STATUS
approved