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A131963 Expansion of psi(q^4)* phi(-q^3)/ chi(q) in powers of q where phi(), psi(), chi() are Ramanujan theta functions. +0
5
1, 1, 1, 0, 1, 2, 1, 1, 0, 1, 0, 1, 2, 1, 1, 1, 1, 1, 0, 2, 0, 0, 1, 0, 2, 1, 3, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 2, 2, 1, 1, 0, 1, 1, 1, 2, 0, 0, 1, 1, 2, 0, 0, 2, 0, 1, 0, 1, 1, 2, 2, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 3, 0, 1, 0, 0, 1, 2, 2, 0, 1, 1, 2, 0, 0, 2, 0, 2, 1, 0, 1, 1, 2, 1, 0, 1, 2, 1, 0, 0, 2 (list; graph; listen)
OFFSET

0,6

FORMULA

Expansion of q^(-13/24)* eta(q^2)* eta(q^3)^2* eta(q^8)^2/( eta(q)* eta(q^4)* eta(q^6)) in powers of q.

Euler transform of period 24 sequence [ 1, 0, -1, 1, 1, -1, 1, -1, -1, 0, 1, 0, 1, 0, -1, -1, 1, -1, 1, 1, -1, 0, 1, -2, ...].

a(25n+13)= a(n). a(25n+3)= a(25n+8)= a(25n+18)= a(25n+23)= 0.

PROGRAM

(PARI) {a(n)= if(n<0, 0, n=24*n+13; sumdiv(n, d, kronecker( -12, d)*(n/d %2))/2)}

(PARI) {a(n)= local(A); if(n<0, 0, A= x*O(x^n); polcoeff( eta(x^2+A)* eta(x^3+A)^2* eta(x^8+A)^2/ eta(x+A)/ eta(x^4+A)/ eta(x^6+A), n))}

CROSSREFS

Cf. A123484(24n+13)= 2*a(n).

Sequence in context: A124761 A156709 A081400 this_sequence A130538 A078659 A079690

Adjacent sequences: A131960 A131961 A131962 this_sequence A131964 A131965 A131966

KEYWORD

nonn

AUTHOR

Michael Somos, Aug 02 2007

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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