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Search: id:A143562
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| A143562 |
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G.f. satisfies: A(x) = 1 + x*A(x)^3/A(-x)^2. |
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+0
1
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| 1, 1, 5, 17, 105, 481, 3261, 16801, 119697, 656129, 4819061, 27447601, 205776121, 1202943457, 9152680109, 54524185409, 419491297313, 2534963932417, 19673179986661, 120224135048273, 939543098579081, 5793676726569697
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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G.f. satisfies: A(x) + A(-x) = 1 + (1+x^2)*A(x)*A(-x).
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EXAMPLE
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G.f. A(x) = 1 + x + 5*x^2 + 17*x^3 + 105*x^4 + 481*x^5 + 3261*x^6 +...
A(x)*A(-x) = 1 + 9*x^2 + 201*x^4 + 6321*x^6 + 233073*x^8 +...
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PROGRAM
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(PARI) {a(n)=local(A=1+x*O(x^n)); for(i=0, n, A=1+x*A^3/subst(A^2, x, -x)); polcoeff(A, n)}
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CROSSREFS
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Sequence in context: A145986 A034821 A158007 this_sequence A098028 A100301 A096178
Adjacent sequences: A143559 A143560 A143561 this_sequence A143563 A143564 A143565
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Aug 24 2008
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