A203581 Vandermonde sequence using x^2 + xy + y^2 applied to (2,3,...,n+1).

1, 19, 19684, 2294583564, 51987957606172224, 354256491848971529923455168, 1043097707370582731107248079473888804864, 1807964167474441339593635811814833549204957259332698112

Offset

1,2

Comments

See A093883 for a discussion and guide to related sequences.

Links

Table of n, a(n) for n=1..8.

Mathematica

f[j_] := j + 1; z = 12;
v[n_] := Product[Product[f[j]^2 + f[j] f[k] + f[k]^2,
{j, 1, k - 1}], {k, 2, n}]
Table[v[n], {n, 1, z}]          (* A203581 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203582 *)

Crossrefs

Sequence in context: A110392 A107100 A233233 * A125043 A249907 A233105

Adjacent sequences: A203578 A203579 A203580 * A203582 A203583 A203584

Keyword

nonn

Author

Clark Kimberling, Jan 04 2012

Status

approved