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A093065
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Expansion of (eta(q^3)eta(q^15)/(eta(q)eta(q^5)))^2 in powers of q.
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0
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1, 2, 5, 8, 16, 28, 48, 78, 124, 194, 302, 454, 682, 996, 1457, 2096, 2993, 4226, 5920, 8228, 11373, 15580, 21246, 28740, 38731, 51872, 69155, 91716, 121105, 159208, 208512, 271894, 353338, 457336, 590124, 758792, 972677, 1242896, 1583576
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Euler transform of period 15 sequence [2,2,0,2,4,0,2,2,0,4,2,0,2,2,0,...].
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FORMULA
| G.f. A(x) satisfies 0=f(A(x), A(x^2)) where f(u, v)=u^3+v^3-4uv(u+v)-9u^2v^2-uv.
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PROG
| (PARI) {a(n)=local(A); if(n<1, 0, n--; A=x*O(x^n); polcoeff((eta(x^3+A)*eta(x^15+A)/eta(x+A)/eta(x^5+A))^2, n))}
(PARI) {a(n)=local(A, u, v); if(n<0, 0, A=x; for(k=2, n, u=A+x*O(x^k); v=subst(u, x, x^2); A-=x^k*polcoeff(u^3+v^3-4*u*v*(u+v)-9*u^2*v^2-u*v, k+2)/2); polcoeff(A, n))}
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CROSSREFS
| Sequence in context: A096541 A137685 A169826 * A026007 A032233 A026530
Adjacent sequences: A093062 A093063 A093064 * A093066 A093067 A093068
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KEYWORD
| nonn
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AUTHOR
| Michael Somos, Mar 17 2004
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