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A129666 Expansion of unique cusp form of weight 4 level 7 in powers of q. +0
1
1, -1, -2, -7, 16, 2, -7, 15, -23, -16, -8, 14, 28, 7, -32, 41, 54, 23, -110, -112, 14, 8, 48, -30, 131, -28, 100, 49, -110, 32, 12, -161, 16, -54, -112, 161, -246, 110, -56, 240, 182, -14, 128, 56, -368, -48, 324, -82, 49, -131, -108, -196, -162, -100, -128, -105, 220, 110, 810, 224, -488, -12 (list; graph; listen)
OFFSET

1,3

REFERENCES

H. Rosson, G. Tornaria, Central values of quadratic twists for a modular form of weight 4, pp. 315-321 of J. B. Conrey, et. al.,ed., Ranks of Elliptic Curves and Random Matrix Theory, Cambridge University Press, 2007..

FORMULA

Expansion of q * phi(-q)^3 * psi(q) * phi(-q^7)^3 * psi(q^7) + 4*q^2 * (phi(-q) * psi(q) * phi(-q^7) * psi(q^7))^2 in powers of q.

Expansion of ((eta(q) * eta(q^7))^3 +4 * (eta(q^2) * eta(q^14))^3) * (eta(q) * eta(q^7))^2/ (eta(q^2) * eta(q^14)) in powers of q.

a(n) is multiplicative with a(7^e) = (-7)^e, a(p^e) = a(p)*a(p^(e-1)) -p^3*a(p^(e-2)).

G.f. is Fourier series of a weight 4 level 7 cusp form. f(-1/ (7 t)) = 49 t^4 f(t) where q = exp(2 pi i t) .

G.f. A(x) satisfies 0 = f(A(x), A(x^2), A(x^4)) where f(u, v, w) = (u^2 + 2*u*v + 16*u*w + 12*v^2 + 32*v*w + 256*w^2)*(-v^3 + 2*w*u*v + w*u^2 + 16*w^2*u) +2*v^5.

EXAMPLE

q - q^2 - 2*q^3 - 7*q^4 + 16*q^5 + 2*q^6 - 7*q^7 + 15*q^8 - 23*q^9 - ...

PROGRAM

(PARI) {a(n)= local(A, A1, A2); if(n<1, 0, n--; A= x*O(x^n); A1= eta(x+A)* eta(x^7+A); A2= eta(x^2+A)* eta(x^14+A); polcoeff( (A1^3 +4*x*A2^3)* A1^2/A2, n))}

CROSSREFS

Convolution of A002652 and A002656.

Adjacent sequences: A129663 A129664 A129665 this_sequence A129667 A129668 A129669

Sequence in context: A050612 A120110 A047694 this_sequence A135781 A041573 A041341

KEYWORD

sign,mult

AUTHOR

Michael Somos, Apr 27 2007

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Last modified November 8 07:45 EST 2009. Contains 166143 sequences.


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