OFFSET
0,3
FORMULA
a(n) = Sum_{j=0..n} A132393(2n,j). - Alois P. Heinz, Dec 10 2021
MAPLE
b:= proc(n, k) option remember; `if`(n=0, 1, `if`(k=0, 0,
add(b(n-j, k-1)*binomial(n-1, j-1)*(j-1)!, j=1..n)))
end:
a:= n-> b(2*n, n):
seq(a(n), n=0..15); # Alois P. Heinz, Dec 09 2021
MATHEMATICA
a[n_] := Sum[Abs[StirlingS1[2*n, j]], {j, 0, n}]; Array[a, 16, 0] (* Amiram Eldar, Dec 09 2021 *)
PROG
(PARI) a(n) = sum(j=0, n, abs(stirling(2*n, j, 1))); \\ Michel Marcus, Dec 09 2021
(Python)
from sympy.functions.combinatorial.numbers import stirling
def A349783(n): return sum(abs(stirling(2*n, j, kind=1)) for j in range(n+1)) # Chai Wah Wu, Dec 09 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Dec 09 2021
STATUS
approved