OFFSET
0,3
COMMENTS
This is the 4-dimensional Elkies_C lattice.
LINKS
John Cannon, Table of n, a(n) for n = 0..5000
N. D. Elkies, Elliptic and modular curves over finite fields and related computational issues, in AMS/IP Studies in Advanced Math., 7 (1998), 21-76, esp. p. 57.
EXAMPLE
G.f. = 1 + 4*x^2 + 6*x^3 + 2*x^4 + 6*x^5 + 2*x^6 + 6*x^7 + 10*x^8 + 2*x^9 + ...
G.f. = 1 + 4*q^4 + 6*q^6 + 2*q^8 + 6*q^10 + 2*q^12 + 6*q^14 + 10*q^16 + ...
PROG
(PARI) {a(n) = my(G); if( n<0, 0, G = [ 4, 1, 2, 1; 1, 4, 1, 0; 2, 1, 6, -2; 1, 0, -2, 20]; polcoeff( 1 + 2 * x * Ser( qfrep( G, n, 1)), n))}; /* Michael Somos, Apr 02 2006 */
(Magma) A := Basis( ModularForms( Gamma0(37), 2), 71); A[1] + 4*A[3]; /* Michael Somos, Mar 30 2015 */
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 22 2000
STATUS
approved