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A115125
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A sequence related to Catalan numbers A000108.
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1
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1, 2, 4, 16, 80, 448, 2688, 16896, 109824, 732160, 4978688, 34398208, 240787456, 1704034304, 12171673600, 87636049920, 635361361920, 4634400522240, 33985603829760, 250420238745600, 1853109766717440
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| 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)
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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]
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CROSSREFS
| Essentially identical to A025225.
Sequence in context: A102736 A103619 A027436 * A025225 A000831 A000090
Adjacent sequences: A115122 A115123 A115124 * A115126 A115127 A115128
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KEYWORD
| nonn,easy
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AUTHOR
| Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Jan 13 2006
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