A370556 a(n) is the denominator 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.

1, 2, 9, 144, 72, 2592, 63504, 4064256, 164602368, 658409472, 39833773056, 5736063320064, 2868031660032, 562134205366272, 2529603924148224, 647578604581945344, 323789302290972672, 104907733942275145728, 18935845976580663803904, 302973535625290620862464, 66805664605376581900173312

Offset

1,2

Links

Table of n, a(n) for n=1..21.

Prog

(PARI) a370556(n) = my (f(n)=prod(k=1, n, 1/k + I)); denominator(f(n)*conj(f(n)))

Crossrefs

A370555 are the corresponding numerators.

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

Sequence in context: A110817 A189428 A110860 * A050995 A376321 A174954

Adjacent sequences: A370553 A370554 A370555 * A370557 A370558 A370559

Keyword

nonn,frac,easy

Author

Hugo Pfoertner, Feb 23 2024

Status

approved