A238685 a(n) = n! * A129505(n) * (-1)^(n+1).

1, -6, 210, -17640, 2693880, -649479600, 226750764240, -108116216208000, 67478689070432640, -53382381970299782400, 52192613508738839136000, -61794396463636399635072000, 87121906773549083421777792000, -144222462676882552982237906688000

Offset: 1

Author

Reinhard Zumkeller, Mar 02 2014

Keywords

• sign

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A000142, A008275, A048594, A129505.

Programs

Haskell

a238685 n = a000142 n * a008275 (2 * n - 1) n

Mathematica

Array[#!*StirlingS1[2 # - 1, #] &, 14] (* Michael De Vlieger, Jan 24 2022 *)

PARI

a(n) = n!*stirling(2*n-1,n, 1); \\ Michel Marcus, Jan 24 2022

Python

from math import factorial
from sympy.functions.combinatorial.numbers import stirling
def A238685(n): return factorial(n)*stirling((n<<1)-1,n,kind=1,signed=True) # Chai Wah Wu, Jun 09 2025

Formula

a(n) = A000142(n) * A008275(2*n-1,n).

a(n) = A048594(2*n-1,n).