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A342288 C(n)*C(n+2), where C(n) is the n-th Catalan number A000108(n). 2
2, 5, 28, 210, 1848, 18018, 188760, 2085798, 24018280, 285817532, 3493769552, 43672119400, 556315613280, 7202300350500, 94561966954800, 1256886144107550, 16888191533829000, 229116465142280100, 3135277944052254000, 43238333101156993800, 600502564063273528800 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..20.

FORMULA

a(n) = a(n-1)*4*(2*n-1)*(2*n+3)/((n+1)*(n+3)). - Chai Wah Wu, Mar 26 2021

PROG

(Python)

A342288_list = [2]

for n in range(1, 100): A342288_list.append(A342288_list[-1]*4*(2*n-1)*(2*n+3)//((n+1)*(n+3))) # Chai Wah Wu, Mar 26 2021

CROSSREFS

Inspired by A000108, A005568, A014228.

Sequence in context: A019043 A009635 A216401 * A324264 A138293 A316972

Adjacent sequences:  A342285 A342286 A342287 * A342289 A342290 A342291

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 26 2021

STATUS

approved

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Last modified July 30 17:21 EDT 2021. Contains 346359 sequences. (Running on oeis4.)