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A136028 Expansion of (phi(q) * phi(q^2))^3 in powers of q where phi() is a Ramanujan theta function. +0
1
1, 6, 18, 44, 90, 144, 212, 288, 330, 418, 528, 588, 836, 1008, 1056, 1440, 1386, 1356, 1894, 1644, 2064, 2880, 2484, 3168, 3428, 2838, 3696, 3864, 4128, 5040, 5280, 5760, 5418, 5656, 5988, 5376, 7678, 8208, 7572, 10080, 8208, 7788, 10560, 8652, 10404 (list; graph; listen)
OFFSET

0,2

FORMULA

Expansion of (eta(q^2) * eta(q^4))^9 / (eta(q) * eta(q^8))^6 in powers of q.

G.f. is Fourier series of a weight 3 level 8 modular form. f(-1/(8 t)) = 2^(9/2) (t/i)^3 f(t) where q = exp(2 pi i t).

G.f.: (Product_{k>0} (1 - x^k)^2 * (1 + x^k)^4 * (1 + x^(2*k)) / (1 + x^(4*k))^2)^3.

EXAMPLE

1 + 6*q + 18*q^2 + 44*q^3 + 90*q^4 + 144*q^5 + 212*q^6 + 288*q^7 + ...

PROGRAM

(PARI) {a(n) = local(A); if( n<0, 0, A = x * O(x^n); polcoeff( ((eta(x^2 + A) * eta(x^4 + A))^3 / (eta(x + A) * eta(x^8 + A))^2)^3, n))}

CROSSREFS

Convolution of A033715 and A097057. a(n) = A029713(n) + 6 * A030207(n).

Sequence in context: A009957 A011929 A070735 this_sequence A083719 A095170 A128543

Adjacent sequences: A136025 A136026 A136027 this_sequence A136029 A136030 A136031

KEYWORD

nonn

AUTHOR

Michael Somos, Dec 10 2007

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Last modified March 20 09:10 EDT 2010. Contains 173642 sequences.


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