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Search: id:A122856
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| A122856 |
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Expansion of (chi(q)psi(-q^3))^2 in powers of q where chi(),psi() are Ramanujan theta functions. |
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+0
8
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| 1, 2, 1, 0, 0, 2, 2, 0, 2, 2, 1, 0, 0, 2, 0, 0, 3, 2, 0, 0, 0, 4, 2, 0, 2, 0, 2, 0, 0, 2, 0, 0, 1, 2, 2, 0, 0, 2, 2, 0, 2, 4, 1, 0, 0, 2, 0, 0, 2, 2, 0, 0, 0, 0, 2, 0, 4, 2, 0, 0, 0, 4, 0, 0, 2, 2, 3, 0, 0, 0, 2, 0, 2, 4, 0, 0, 0, 2, 0, 0, 1, 2, 0, 0, 0, 2, 4, 0, 0, 2, 2, 0, 0, 2, 0, 0, 4, 2, 2, 0, 0, 4, 0, 0, 2
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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Expansion of q^(-2/3)(eta(q^2)^2*eta(q^3)*eta(q^12)/(eta(q)eta(q^4)eta(q^6)))^2 in powers of q.
Euler transform of period 12 sequence [ 2, -2, 0, 0, 2, -2, 2, 0, 0, -2, 2, -2, ...].
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PROGRAM
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(PARI) {a(n)=if(n<0, 0, n=3*n+2; sumdiv(n, d, (d%4==1)-(d%4==3)))}
(PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff( (eta(x^2+A)^2*eta(x^3+A)*eta(x^12+A)/(eta(x+A)*eta(x^4+A)*eta(x^6+A)))^2, n))}
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CROSSREFS
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A002654(3n+2)=A035154(3n+2)=A113446(3n+2)=a(n).
Sequence in context: A123484 A008626 A058626 this_sequence A055791 A120730 A122851
Adjacent sequences: A122853 A122854 A122855 this_sequence A122857 A122858 A122859
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Sep 14 2006
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