A028642 Expansion of (theta_3(z)*theta_3(19z) + theta_2(z)*theta_2(19z))^2.

1, 4, 4, 0, 4, 16, 16, 8, 20, 20, 24, 24, 48, 8, 32, 16, 52, 16, 52, 4, 40, 48, 48, 32, 80, 52, 56, 64, 80, 56, 96, 32, 84, 48, 72, 56, 116, 56, 4, 96, 120, 40, 128, 56, 96, 112, 96, 56, 144, 60, 124, 112, 152, 104, 160, 120, 160, 0, 120, 64, 256, 80, 128, 136

Offset

0,2

Links

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

Prog

(PARI) a(n) = if( n<0, 0, polcoeff( (1 + 2 * x * Ser(qfrep( [ 2, 1; 1, 10], n, 1)))^2, n)); \\ Jinyuan Wang, Feb 19 2020

Crossrefs

Cf. A028643, A028644.

Sequence in context: A169784 A236929 A351521 * A159796 A069523 A021231

Adjacent sequences: A028639 A028640 A028641 * A028643 A028644 A028645

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Jinyuan Wang, Feb 19 2020

Status

approved