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Search: id:A053984
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A053984 a(n)=(2*n-1)*a(n-1)-a(n-2), a(0)=0, a(1)=1. +0
6
0, 1, 3, 14, 95, 841, 9156, 118187, 1763649, 29863846, 565649425, 11848774079, 271956154392, 6787055085721, 182978531160075, 5299590348556454, 164104322274089999, 5410143044696413513, 189190902242100382956 (list; graph; listen)
OFFSET

0,3

COMMENT

Numerators of successive convergents to tan(1) using continued fraction 1/(1-1/(3-1/(5-1/(7-1/(9-1/(11-1/(13-1/15-...))))))).

Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 20 2009: (Start)

Equals eigensequence of an infinite lower triangular matrix with

(1, 3, 5, 7,...) as the main diagonal and (0, -1, -1, -1,...) as the subdiagonal. (End)

FORMULA

E.g.f.: sin(1-sqrt(1-2*x))/sqrt(1-2*x). Cf. A036244. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 10 2006

EXAMPLE

a(10)=565649425 because 1/(1-1/(3-1/(5-1/(7-1/(9-1/(11-1/(13-1/(15-1/(17-1/19)))))))))=565649425/363199319

CROSSREFS

A053984(n)=(-1)^n*A053983(-1-n). A053983(n)=-(-1)^n*A053984(-1-n).

Cf. A053983.

Sequence in context: A091906 A094369 A005772 this_sequence A113181 A136461 A007470

Adjacent sequences: A053981 A053982 A053983 this_sequence A053985 A053986 A053987

KEYWORD

easy,frac,nonn

AUTHOR

Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 02 2000

EXTENSIONS

Additional comments from Michael Somos, Aug 23, 2000

More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 10 2006

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.


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