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A145726
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Expansion of q * psi(-q) * psi(-q^15) / (psi(-q^3) * psi(-q^5)) in powers of q where psi() is a Ramanujan theta function.
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3
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1, -1, 0, 0, -1, 1, 0, -1, 0, 1, 0, 0, 1, -2, 1, 2, -3, 1, 1, -2, 3, 0, -3, 1, 2, -2, 0, 2, -6, 3, 4, -7, 3, 2, -5, 6, 2, -8, 3, 5, -6, 2, 4, -12, 7, 10, -15, 6, 5, -13, 12, 4, -18, 7, 11, -14, 6, 10, -24, 14, 20, -32, 12, 12, -29, 24, 9, -36, 15, 22, -30, 13, 22, -50, 27, 36, -63, 26, 24, -56, 45, 22, -69, 30, 42, -62, 27
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OFFSET
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1,14
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COMMENTS
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LINKS
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FORMULA
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Expansion of eta(q) * eta(q^4) * eta(q^6) * eta(q^10) * eta(q^15) * eta(q^60) / (eta(q^2) * eta(q^3) * eta(q^5) * eta(q^12) * eta(q^20) * eta(q^30)) in powers of q.
Euler transform of a period 60 sequence.
G.f. is a period 1 Fourier series which satisfies f(-1 / (60 t)) = f(t) where q = exp(2 Pi i t).
G.f.: x * Product_{k>0} P(15, x^k) * P(60, x^k) where P(n, x) is the n-th cyclotomic polynomial.
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EXAMPLE
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q - q^2 - q^5 + q^6 - q^8 + q^10 + q^13 - 2*q^14 + q^15 + 2*q^16 - 3*q^17 + ...
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PROG
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(PARI) {a(n) = local(A); if( n<1, 0, n--; A = x * O(x^n); polcoeff( eta(x + A) * eta(x^4 + A) * eta(x^6 + A) * eta(x^10 + A) * eta(x^15 + A) * eta(x^60 + A) / (eta(x^2 + A) * eta(x^3 + A) * eta(x^5 + A) * eta(x^12 + A) * eta(x^20 + A) * eta(x^30 + 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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