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A156215
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Expansion of (chi(q^3) / chi(q))^6 + q / (chi(q^3) / chi(q))^6 in powers of q where chi() is a Ramanujan theta function.
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1
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1, -5, 27, -41, 146, -243, 510, -887, 1755, -2728, 5052, -7857, 13157, -20253, 32805, -48680, 76568, -112320, 169814, -246263, 365013, -519046, 755632, -1063368, 1516404, -2112551, 2972160, -4089098, 5683166, -7750782, 10633276, -14382932, 19539387
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OFFSET
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0,2
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COMMENTS
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Denoted by "(24~e)" in Simon Norton's replicable function list.
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LINKS
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FORMULA
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Expansion of (chi(q) * chi(q^3))^3 - 8 * q / (chi(q) * chi(q^3))^3 in powers of q where chi() is a Ramanujan theta function.
G.f. is a period 1 Fourier series which satisfies f(-1 / (48 t)) = f(t) where q = exp(2 Pi i t).
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EXAMPLE
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G.f. = 1 - 5*x + 27*x^2 - 41*x^3 + 146*x^4 - 243*x^5 + 5120*x^6 + ...
G.f. = 1/q - 5*q + 27*q^3 - 41*q^5 + 146*q^7 - 243*q^9 + 510*q^11 - 887*q^13 + ...
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PROG
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(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); A = ((eta(x^2 + A) * eta(x^6 + A))^2 / (eta(x + A) * eta(x^3 + A) * eta(x^4 + A) * eta(x^12 + A)))^3; polcoeff( A - 8 * x / A, n))};
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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