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A099765
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a(n)=(1/Pi)*(2^n/n)*(n-1)!*integral((sin(t)/t)^n dt, t=0.....infty).
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1
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1, 1, 2, 8, 46, 352, 3364, 38656, 519446, 7996928, 138826588, 2683604992, 57176039628, 1331300646912, 33636118326984, 916559498182656, 26795449170328038, 836606220759859200, 27784046218331805100
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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REFERENCES
| Sergey Fomin and Grigory Mikhalkin, Labeled floor diagrams for plane curves, arXiv:0906.3828. See Section 8. [From N. J. A. Sloane, Sep 27 2010]
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LINKS
| W. Trump, Magic series.
Eric Weisstein's World of Mathematics, Sinc Function
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FORMULA
| a(n)=(1/n)*sum(k=0, floor(n/2), (-1)^k*binomial(n, k)*(n-2*k)^(n-1))
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MATHEMATICA
| Table[1/n Sum[(-1)^k Binomial[n, k](n-2k)^(n-1), {k, 0, Floor[n/2]}], {n, 20}] (* From Harvey P. Dale, Oct 21 2011 *)
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PROG
| (PARI) a(n)=(1/n)*sum(k=0, floor(n/2), (-1)^k*binomial(n, k)*(n-2*k)^(n-1))
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CROSSREFS
| Cf. A049330.
Sequence in context: A180390 A074599 A007289 * A096656 A102009 A135904
Adjacent sequences: A099762 A099763 A099764 * A099766 A099767 A099768
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 11 2004, Dec 11 2007
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