A227325 a(n) = A000272(n+1) * A000984(n).

1, 2, 18, 320, 8750, 326592, 15529668, 899678208, 61556811030, 4862000000000, 435644983598396, 43678490079264768, 4846281282497517772, 589650705050503577600, 78074729079345703125000, 11177395284330167371038720, 1720546364146510165684599270

Offset: 0

Author

Reinhard Zumkeller, Jul 07 2013

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..250

Crossrefs

Cf. A000272, A000984.

Central terms of triangle A088956.

Programs

Haskell

a227325 n = a000272 (n + 1) * a000984 n

Formula

a(n) = A088956(2*n, n) = (n+1)^(n-1) * C(2*n, n).

Extensions

Typo in formula fixed by Zak Seidov, Jul 08 2013