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A081293 a(n) = A000108(n) + A014137(n). 2
2, 3, 6, 14, 37, 107, 329, 1055, 3486, 11780, 40510, 141286, 498524, 1776312, 6382292, 23097542, 84118037, 308049947, 1133682557, 4190570237, 15551547887, 57919961507, 216418821767, 811055485427, 3047804166425, 11481792822005 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..25.

Guo-Niu Han, Enumeration of Standard Puzzles, 2011. [Cached copy]

Guo-Niu Han, Enumeration of Standard Puzzles, arXiv:2006.14070 [math.CO], 2020.

FORMULA

a(n) = 2*A000108(n) + A014137(n-1). - Michel Marcus, Apr 28 2020

PROG

(PARI) Cat(n) = binomial(2*n, n)/(n+1); \\ A000108

a(n) = Cat(n)+sum(k=0, n, Cat(k)); \\ Michel Marcus, Apr 28 2020

CROSSREFS

Cf. A000108, A014137, A081289.

Sequence in context: A337186 A049339 A157100 * A193215 A007611 A098641

Adjacent sequences:  A081290 A081291 A081292 * A081294 A081295 A081296

KEYWORD

nonn

AUTHOR

Antti Karttunen, Mar 17 2003

STATUS

approved

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Last modified May 13 17:46 EDT 2021. Contains 343864 sequences. (Running on oeis4.)