A370555 - OEIS

%I #8 Feb 23 2024 07:10:07

%S 2,5,25,425,221,8177,204425,13287625,544792625,2200962205,

%T 134258694505,19467510703225,9791351537125,1928896252813625,

%U 8718611062717585,2240683043118419345,1124218135820660225,365370894141714573125,66132131839650337735625,1060759394707991417279425

%N a(n) is the numerator of f(n)*conj(f(n)), where f(n) = Product_{k=1..n} (1/k + i), i is the imaginary unit, and conj(z) is the complex conjugate of z.

%C f(n) may also be chosen as Product_{k=1..n} (1 + i/k) without changing the result.

%o (PARI) a370555(n) = my (f(n)=prod(k=1, n, 1/k+I)); numerator(f(n)*conj(f(n)))

%Y A370556 are the corresponding denominators.

%Y Cf. A370547, A370548, A370549, A370550, A370551, A370552, A370553, A370554.

%K nonn,frac,easy

%O 1,1

%A _Hugo Pfoertner_, Feb 23 2024