A028658 Expansion of (theta_3(z)*theta_3(23z) + theta_2(z)*theta_2(23z))^2.

1, 4, 4, 0, 4, 8, 8, 16, 12, 20, 24, 0, 40, 24, 32, 16, 36, 24, 44, 16, 40, 16, 32, 4, 80, 28, 48, 48, 48, 24, 80, 48, 84, 80, 56, 64, 92, 40, 64, 48, 88, 40, 96, 48, 112, 88, 4, 48, 120, 68, 92, 80, 96, 56, 136, 64, 112, 96, 96, 80, 192, 56, 120, 128, 140, 96

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

References

• Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See F_2, p. 195.

Links

• Jinyuan Wang, Table of n, a(n) for n = 0..1000

Programs

PARI

a(n) = if( n<0, 0, polcoeff( (1 + 2 * x * Ser(qfrep( [ 2, 1; 1, 12], n, 1)))^2, n)); \\ Jinyuan Wang, Feb 19 2020

Extensions

More terms from Jinyuan Wang, Feb 19 2020