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A122792
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Expansion of eta(q^2)^2/(eta(q)eta(q^3)) in powers of q.
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0
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1, 1, 0, 2, 1, 0, 4, 2, 0, 6, 4, 0, 10, 6, 0, 16, 9, 0, 24, 14, 0, 36, 20, 0, 52, 29, 0, 74, 42, 0, 104, 58, 0, 144, 80, 0, 198, 110, 0, 268, 148, 0, 360, 198, 0, 480, 264, 0, 634, 347, 0, 832, 454, 0, 1084, 592, 0, 1404, 764, 0, 1808, 982, 0, 2316, 1257, 0, 2952, 1598, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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FORMULA
| Euler transform of period 6 sequence [ 1, -1, 2, -1, 1, 0, ...].
G.f.: Product_{k>0} (1-x^k)^2/(1+x^k+x^(2k)). a(3n+2)=0.
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PROG
| (PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff( eta(x^2+A)^2/eta(x+A)/eta(x^3+A), n))}
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CROSSREFS
| A098151(n)=a(3n). A097197(n)=a(3n+1).
Sequence in context: A136329 A122073 A106236 * A139136 A138002 A062296
Adjacent sequences: A122789 A122790 A122791 * A122793 A122794 A122795
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KEYWORD
| nonn
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AUTHOR
| Michael Somos, Sep 11 2006
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