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A227791 Central terms of the triangle in A227550. 3
1, 2, 8, 36, 176, 940, 5568, 37128, 280992, 2410812, 23250080, 249164344, 2934303264, 37617633976, 521009920256, 7748175156240, 123095897716800, 2080205257723740, 37253560076385120, 704703668205036120, 14039778681732928800, 293831851498842784680 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) = A074911(2*n,n).

LINKS

Table of n, a(n) for n=0..21.

MAPLE

b:= proc(x, y) option remember; `if`(x=0, y!,

      b(x-1, y)+b(sort([x, y-1])[]))

    end:

a:= n-> b(n$2):

seq(a(n), n=0..26);  # Alois P. Heinz, Jul 14 2021

PROG

(Haskell)

a227791 n = a227550 (2 * n) n

CROSSREFS

Cf. A225621.

Sequence in context: A166229 A109318 A113327 * A245102 A129148 A285672

Adjacent sequences:  A227788 A227789 A227790 * A227792 A227793 A227794

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Aug 05 2013

STATUS

approved

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Last modified May 22 22:13 EDT 2022. Contains 353959 sequences. (Running on oeis4.)