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Search: id:A105523
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| A105523 |
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Expansion of 1-xc(-x^2) where c(x) is the g.f. of A000108. |
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+0
11
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| 1, -1, 0, 1, 0, -2, 0, 5, 0, -14, 0, 42, 0, -132, 0, 429, 0, -1430, 0, 4862, 0, -16796, 0, 58786, 0, -208012, 0, 742900, 0, -2674440, 0, 9694845, 0, -35357670, 0, 129644790, 0, -477638700, 0, 1767263190, 0
(list; graph; listen)
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OFFSET
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0,6
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COMMENT
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Row sums of A105522. Row sums of inverse of A105438.
First column of number triangle A106180.
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FORMULA
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G.f.: (1+2x-sqrt(1+4x^2))/(2x)
a(n)=0^n+sin(pi*(n-2)/2)(C((n-1)/2)(1-(-1)^n)/2);
G.f.: 1/(1+x/(1-x/(1+x/(1-x/(1+x/(1-x.... (continued fraction). [From Paul Barry (pbarry(AT)wit.ie), Jan 15 2009]
a(n)=sum{k=0..n, A090181(n,k)*(-1)^k}. [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Feb 02 2009]
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CROSSREFS
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Cf. A097331, A090192.
Sequence in context: A078153 A104035 A115333 this_sequence A126120 A090192 A097331
Adjacent sequences: A105520 A105521 A105522 this_sequence A105524 A105525 A105526
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KEYWORD
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easy,sign
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Apr 11 2005
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