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Search: id:A097801
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A097801 (2*n)!/(n!*2^(n-1)). +0
5
2, 2, 6, 30, 210, 1890, 20790, 270270, 4054050, 68918850, 1309458150, 27498621150, 632468286450, 15811707161250, 426916093353750, 12380566707258750, 383797567925021250, 12665319741525701250, 443286190953399543750, 16401589065275783118750, 639661973545755541631250 (list; graph; listen)
OFFSET

0,1

REFERENCES

Right-hand edge of triangle in A097749.

FORMULA

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Nov 12 2009: (Start)

a(n) = 2*(2*n-1)!!

(End)

CROSSREFS

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Nov 12 2009: (Start)

Equals 2*A001147.

Appears in A167576.

(End)

Sequence in context: A108800 A058250 A067644 this_sequence A164347 A052584 A094303

Adjacent sequences: A097798 A097799 A097800 this_sequence A097802 A097803 A097804

KEYWORD

nonn,new

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Sep 21 2004

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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