A203673 Vandermonde sequence using x^2 + xy + y^2 applied to (1,4,9,...,n^2).

1, 21, 254163, 11213968422384, 6451450005117349260375984, 127857993263632065817610313129228311433216, 191199773886534869435599958788731398661833328276349525268803584

Offset

1,2

Comments

See A093883 for a discussion and guide to related sequences.

Links

Table of n, a(n) for n=1..7.

Mathematica

f[j_] := j^2; z = 12;
u[n_] := Product[f[j]^2 + f[j] f[k] + f[k]^2, {j, 1, k - 1}]
v[n_] := Product[u[n], {k, 2, n}]
Table[v[n], {n, 1, z}]          (* A203673 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203674 *)

Crossrefs

Sequence in context: A013768 A182149 A358665 * A172854 A143736 A189252

Adjacent sequences: A203670 A203671 A203672 * A203674 A203675 A203676

Keyword

nonn

Author

Clark Kimberling, Jan 04 2012

Status

approved