A028718 Expansion of (theta_3(z)*theta_3(7z)*theta_3(49z)+theta_2(z)*theta_2(7z)*theta_2(49z)).

1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 4, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 6, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,5

Links

Antti Karttunen, Table of n, a(n) for n = 0..11958

Example

G.f. = 1 + 2*q^4 + 2*q^16 + 2*q^28 + 4*q^32 + 2*q^36 + 4*q^44 + 8*q^57 + 6*q^64 + 8*q^65 + ... - Michael Somos, Nov 23 2017

Mathematica

a[ n_] := SeriesCoefficient[ EllipticTheta[ 3, 0, q^4] EllipticTheta[ 3, 0, q^28] EllipticTheta[ 3, 0, q^196] + EllipticTheta[ 2, 0, q^4] EllipticTheta[ 2, 0, q^28] EllipticTheta[ 2, 0, q^196], {q, 0, n}]; (* Michael Somos, Nov 23 2017 *)

Prog

(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( (eta(x^8 + A) * eta(x^56 + A) * eta(x^392 + A))^5 / (eta(x^4 + A) * eta(x^16 + A) * eta(x^28 + A) * eta(x^112 + A) * eta(x^196 + A) * eta(x^784 + A))^2 + 8 * x^57 * (eta(x^16 + A) * eta(x^112 + A) * eta(x^784 + A))^2 / (eta(x^8 + A) * eta(x^56 + A) * eta(x^392 + A)), n))}; /* Michael Somos, Nov 23 2017 */

Crossrefs

Cf. A028719, A028720, A028721.

Sequence in context: A179391 A332016 A083850 * A028661 A028714 A028653

Adjacent sequences: A028715 A028716 A028717 * A028719 A028720 A028721

Keyword

nonn

Author

N. J. A. Sloane

Status

approved