%I #9 Feb 22 2024 17:46:26
%S 1,3,0,-5,-3,35,11,-65,-3055,4433,2561,-18863,-614635,14705,3871801,
%T -6702403,-23794993,-21392575,1677354925,2206770805,-30432904645,
%U -617315066615,2099373575975,551582580432325,-11053607615333933,-180184164588301,4198057769186443,435884809756010315
%N a(n) is the numerator of the imaginary part of Product_{k=1..n} (1/k + i) where i is the imaginary unit.
%F a(n) = numerator of A105751(n)/n!. - _Chai Wah Wu_, Feb 22 2024
%e See A370547.
%o (PARI) a370549(n) = numerator(imag(prod(k=1, n, 1/k+I)))
%o (Python)
%o from math import factorial, gcd
%o from sympy.functions.combinatorial.numbers import stirling
%o def A370549(n): return (a:=sum(stirling(n+1,n-(k<<1),kind=1)*(-1 if k&1 else 1) for k in range((n>>1)+1)))//gcd(a,factorial(n)) # _Chai Wah Wu_, Feb 22 2024
%Y Cf. A105751, A370547, A370548, A370550.
%K frac,sign,easy
%O 1,2
%A _Hugo Pfoertner_, Feb 22 2024