OFFSET
0,2
FORMULA
a(n) = 2*n*(2*n-1)*(n-1)!*n! = 2*n^2*(2*n-1)*((n-1)!)^2 for n > 0. a(n) = a(n-1)*n^2*(2*n - 1)/(2*n - 3) for n > 1. - Chai Wah Wu, May 12 2021
MATHEMATICA
a[n_] := (2 n)! / CatalanNumber[n - 1]; a[0] := 1; Table[a[n], {n, 0, 16}]
PROG
(Python)
from math import factorial
def A344057(n):
return 1 if n == 0 else 2*n**2*(2*n-1)*factorial(n-1)**2 # Chai Wah Wu, May 12 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, May 12 2021
STATUS
approved