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Search: id:A111376
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| A111376 |
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Let qf(a,q) = Product(1-a*q^j,j=0..infinity); g.f. is qf(q^3,q^7)*qf(q^5,q^7)*qf(q^6,q^7)/(qf(q,q^7)*qf(q^2,q^7)*qf(q^4,q^7)). |
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+0
2
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| 1, 1, 2, 1, 3, 1, 2, -1, 3, 1, 3, 1, 4, 2, -1, -1, 1, 3, 1, 4, 6, 1, -1, -4, 5, -3, 6, 4, 9, -4, -5, 0, -3, 4, 4, 18, 1, -3, -4, -7, 0, -3, 25, 1, 5, -11, -4, -12, -7, 32, 11, 15, -15, 4, -24, -21, 27, 21, 31, -24, 17, -41, -31, 4, 38, 50, -18, 36, -46, -41, -36, 45, 67, -12, 57, -50, -38, -95, 51, 73, 14, 82, -32, -27, -171, 44
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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Euler transform of period 7 sequence [1, 1, -1, 1, -1, -1, 0, ...]. - Michael Somos Nov 11 2005
G.f.: Product_{k>0} (1-x^(7k-4))(1-x^(7k-2))(1-x^(7k-1))/((1-x^(7k-3))*(1-x^(7k-5))(1-x^(7k-6))) . - Michael Somos Nov 11 2005
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PROGRAM
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(PARI) {a(n)=if(n<0, 0, polcoeff( prod(k=1, n, (1-x^k)^-kronecker(-7, k), 1+x*O(x^n)), n))} /* Michael Somos Nov 11 2005 */
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CROSSREFS
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Cf. A111375.
Sequence in context: A094959 A162696 A108103 this_sequence A157226 A156249 A164677
Adjacent sequences: A111373 A111374 A111375 this_sequence A111377 A111378 A111379
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KEYWORD
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sign
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Nov 09 2005
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