cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Jan 04 2012

Keywords

Comments

See A093883 for a discussion and guide to related sequences.

Programs

  • 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 *)