OFFSET
1,2
FORMULA
a(n) = numerator of A231531(n)/n!. - Chai Wah Wu, Feb 22 2024
EXAMPLE
See A370551.
PROG
(PARI) a370553(n) = numerator(imag(prod(k=1, n, 1+I/k)))
(Python)
from math import factorial, gcd
from sympy.functions.combinatorial.numbers import stirling
def A370553(n): return (a:=sum(stirling(n+1, k<<1, kind=1)*(1 if k&1 else -1) for k in range((n+1>>1)+1)))//gcd(a, factorial(n)) # Chai Wah Wu, Feb 22 2024
CROSSREFS
KEYWORD
frac,sign,easy
AUTHOR
Hugo Pfoertner, Feb 22 2024
STATUS
approved