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Search: id:A125054
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A125054 Central terms of triangle A125053. +0
4
1, 3, 21, 327, 9129, 396363, 24615741, 2068052367, 225742096209, 31048132997523, 5252064083753061, 1071525520294178007, 259439870666594250489, 73542221109962636293083, 24125551094579137082039181 (list; graph; listen)
OFFSET

0,2

COMMENT

Triangle A125053 is a variant of triangle A008301 (enumeration of binary trees) such that the left-most column is the secant numbers (A000364).

FORMULA

Binomial transform of A000182 (e.g.f. tan(x)).

a(n)=Sum_{k, 0<=k<=n}A130847(n,k)*2^k. - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jul 22 2007

CROSSREFS

Cf. A125053, A125055.

Sequence in context: A005329 A134528 A118410 this_sequence A113085 A083228 A101389

Adjacent sequences: A125051 A125052 A125053 this_sequence A125055 A125056 A125057

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Nov 21 2006

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


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