A203679 Vandermonde sequence using x^2 + xy + y^2 applied to (1,2,4,...,2^(n-1)).

1, 7, 4116, 2826802944, 33920193794185101312, 110137716338572837381278474323361792, 1523742153535218423780156082312357202968690791891031031808

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_] := 2^(j - 1); 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}]          (* A203679 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203680 *)

Crossrefs

Sequence in context: A216935 A024100 A069644 * A145696 A361452 A338250

Adjacent sequences: A203676 A203677 A203678 * A203680 A203681 A203682

Keyword

nonn

Author

Clark Kimberling, Jan 04 2012

Status

approved