A390727 a(n) = Stirling2(2*n, n)*(2*n)!/(n+1)!.

1, 1, 28, 2700, 571536, 214326000, 125799886080, 106657796044800, 123488975062252800, 187327646047474732800, 360672808042354114944000, 859499837892824747191372800, 2483997739853162371289966592000, 8560829696851107798143961139200000, 34689216250915892757838200777523200000

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..195

Formula

a(n) = A048993(2*n, n)*A001761(n).

a(n) = A007820(n)*A001761(n).

a(n) = n!*A390277(n).

Maple

A390727 := n -> Stirling2(2*n, n)*(2*n)!/(n+1)!:
seq(A390727(n), n = 0..14);

Mathematica

Table[StirlingS2[2 n, n]*Factorial[2 n]/Factorial[n+1], {n, 0, 15}] (* Vincenzo Librandi, Nov 19 2025 *)

Prog

(Magma) [StirlingSecond(2*n, n)*Factorial(2*n)/Factorial(n+1): n in [0..20]]; // Vincenzo Librandi, Nov 19 2025

Crossrefs

Cf. A390277, A390276, A390276, A048993, A007820, A001761.

Sequence in context: A103660 A317799 A275654 * A283519 A284770 A107444

Adjacent sequences: A390724 A390725 A390726 * A390728 A390729 A390730

Keyword

nonn

Author

Peter Luschny, Nov 16 2025

Status

approved