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A025164 a(n) = a(n-2)+(2n-1)a(n-1); a(0)=1, a(1)=1. +0
2
1, 4, 21, 151, 1380, 15331, 200683, 3025576, 51635475, 984099601, 20717727096, 477491822809, 11958013297321, 323343850850476, 9388929687961125, 291380164177645351, 9624934347550257708, 337164082328436665131 (list; graph; listen)
OFFSET

0,2

COMMENT

Numerator of continued fraction given by C(n) = [ 1;3,5,7,...(2n-1)]. - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 02 2001

Numerators of convergents to coth(1)

Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 17 2009: (Start)

Equals eigensequence of an infinite lower triangular matrix with (1, 3, 5,...)

in the main diagonal, (1, 1, 1,...) in the sum diagonal, and the rest zeros. (End)

FORMULA

E.g.f.: cosh((1-2*x)^(1/2)-1)/(1-2*x)^(1/2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 30 2004

MATHEMATICA

a[ n_ ] := a[ n ] =a[ n-2 ]+(-1+2 n) a[ n-1 ]; a[ 0 ] := 1; a[ 1 ] := 1.

CROSSREFS

Cf. A001040, A001053, A036244, A036244.

Sequence in context: A006879 A163861 A006153 this_sequence A060072 A157503 A144010

Adjacent sequences: A025161 A025162 A025163 this_sequence A025165 A025166 A025167

KEYWORD

nonn

AUTHOR

w.meeussen (wouter.meeussen(AT)pandora.be)

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 15 2001

More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 30 2004

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Last modified November 22 20:51 EST 2009. Contains 167312 sequences.


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