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Search: id:A115125
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A115125 A sequence related to Catalan numbers A000108. +0
2
1, 2, 4, 16, 80, 448, 2688, 16896, 109824, 732160, 4978688, 34398208, 240787456, 1704034304, 12171673600, 87636049920, 635361361920, 4634400522240, 33985603829760, 250420238745600, 1853109766717440 (list; graph; listen)
OFFSET

0,2

COMMENT

The convolution of this sequence with the sequence {(-1)^n} is A064062 (see also A062992).

The sequence A064062 appears in the Derrida et al. 1992 reference (see A064094) for alpha=2, beta =1 (or alpha=1, beta=2)

FORMULA

a(n)=C(n-1)*2^n, n>=1, a(0):=1, with C(n):=A000108(n) (Catalan).

G.f.: 1 + (2*x)*c(2*x) with c(x):=(1-sqrt(1-4*x))/(2*x), the o.g.f. of Catalan numbers A000108.

a(n)=A025225(n), n>0. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 11 2008]

CROSSREFS

Essentially identical to A025225.

Sequence in context: A103619 A027436 A025225 this_sequence A000831 A000090 A013115

Adjacent sequences: A115122 A115123 A115124 this_sequence A115126 A115127 A115128

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Jan 13 2006

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


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