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A132911
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a(n)=(n+1)(2n)!/2^n.
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1
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1, 2, 18, 360, 12600, 680400, 52390800, 5448643200, 735566832000, 125046361440000, 26134689540960000, 6585941764321920000, 1969196587532254080000, 689218805636288928000000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Define T(n,k)=((1+(-1)^n)/2)*C(k-1+n/2, n/2)*n!/2^(n/2). Then T(n,k) has e.g.f. 1/sum{j=0..k, C(k,j)*(-1)^j*x^(2j)/2^j}. T(n,1) is A000680 with interpolated zeros. T(n,3) is A132912.
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FORMULA
| E.g.f.: 1/(1-x^2+x^4/4) (with interpolated zeros);
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CROSSREFS
| Sequence in context: A090307 A123311 A181536 * A152684 A201732 A141074
Adjacent sequences: A132908 A132909 A132910 * A132912 A132913 A132914
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Sep 04 2007
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