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Search: id:A107086
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| A107086 |
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G.f. A(x) satisfies: A(x)^4 = A(x^2)^2 + 4*x. |
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+0
3
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| 1, 1, -1, 2, -5, 13, -35, 99, -289, 857, -2578, 7864, -24252, 75430, -236348, 745431, -2364399, 7536482, -24127482, 77544613, -250098478, 809169322, -2625483810, 8541037140, -27851360659, 91018956200, -298052119611, 977825373366, -3213513271929, 10577811289462, -34870732260397
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Self-convolution is A107087. Self-convolution 4-th power is A107088.
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EXAMPLE
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A(x)^4 = 1 + 4*x + 2*x^2 - x^4 + 2*x^6 - 5*x^8 + 12*x^10 - 30*x^12 +...
A(x^2)^2 = 1 + 2*x^2 - x^4 + 2*x^6 - 5*x^8 + 12*x^10 - 30*x^12 +...
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PROGRAM
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(PARI) {a(n)=local(A=1+x); for(i=1, n, A=(subst(A, x, x^2)+4*x+x*O(x^n))^(1/2)); polcoeff(A, n, x)}
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CROSSREFS
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Cf. A107087, A107088.
Sequence in context: A025198 A037247 A126221 this_sequence A089846 A131868 A000747
Adjacent sequences: A107083 A107084 A107085 this_sequence A107087 A107088 A107089
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KEYWORD
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sign
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), May 11 2005
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