A203759 Vandermonde sequence using x^2 + xy + y^2 applied to (1,1,2,2,...,[n/2]).

1, 3, 147, 86436, 5273373924, 8686528282691532, 4111538282327563523497152, 93412216233151136505901971387334656, 1219854711057286573050999646270927427863304749056

Offset: 1

Author

Clark Kimberling, Jan 05 2012

Keywords

• nonn

Comments

See A093883 for a discussion and guide to related sequences.

Programs

Mathematica

f[j_] := Floor[(j + 1)/2]; z = 13;
u := Product[f[j]^2 + f[j] f[k] + f[k]^2, {j, 1, k - 1}]
v[n_] := Product[u, {k, 2, n}]
Table[v[n], {n, 1, z}]          (* A203759 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203760 *)