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Search: id:A082582
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| A082582 |
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Expansion of (1+x^2-sqrt(1-4x+2x^2+x^4))/(2x) in powers of x. |
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5
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| 1, 1, 1, 2, 5, 13, 35, 97, 275, 794, 2327, 6905, 20705, 62642, 190987, 586219, 1810011, 5617914, 17518463, 54857506, 172431935, 543861219, 1720737981, 5459867166, 17369553427, 55391735455, 177040109419, 567019562429, 1819536774089
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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G.f. A(x) satisfies the equation 0=1-(1+x^2)*A(x)+xA(x)^2.
Series reversion of xA(x) is x*A007477(-x). - Michael Somos, Jul 22 2003
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FORMULA
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G.f.: (1+x^2-sqrt(1-4x+2x^2+x^4))/(2x).
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PROGRAM
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(PARI) a(n)=polcoeff((1+x^2-sqrt(1-4*x+2*x^2+x^4+x^2*O(x^n)))/2, n+1)
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CROSSREFS
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Apart from initial term, same as A025242.
Sequence in context: A091190 A007689 A085281 this_sequence A086581 A059027 A025198
Adjacent sequences: A082579 A082580 A082581 this_sequence A082583 A082584 A082585
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KEYWORD
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easy,nonn
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AUTHOR
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Emanuele Munarini (munarini(AT)mate.polimi.it), May 07 2003
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