OFFSET
1,2
FORMULA
a(n) = denominator of A231531(n)/n!. - Chai Wah Wu, Feb 22 2024
EXAMPLE
See A370551.
PROG
(PARI) a370554(n) = denominator(imag(prod(k=1, n, 1+I/k)))
(Python)
from math import factorial, gcd
from sympy.functions.combinatorial.numbers import stirling
def A370554(n): return (a:=factorial(n))//gcd(a, sum(stirling(n+1, k<<1, kind=1)*(1 if k&1 else -1) for k in range((n+1>>1)+1))) # Chai Wah Wu, Feb 22 2024
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
Hugo Pfoertner, Feb 22 2024
STATUS
approved