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.

A296605 Rectangle read by rows: T(n,k) is the number of n X n diagonalizable matrices over GF(3) that have exactly k distinct eigenvalues, n >= 0, 0 <= k <= 3.

Original entry on oeis.org

1, 0, 0, 0, 0, 3, 0, 0, 0, 3, 36, 0, 0, 3, 702, 1404, 0, 3, 38070, 379080, 0, 3, 5351346, 341368830, 0, 3, 2434569858, 1231457092866, 0, 3, 2987199920970, 17481694843567584, 0, 3, 11966842794993066, 1077553466091961763220
Offset: 0

Views

Author

Geoffrey Critzer, Dec 16 2017

Keywords

Examples

			Array begins:
  1, 0,       0,         0,
  0, 3,       0,         0,
  0, 3,      36,         0,
  0, 3,     702,      1404,
  0, 3,   38070,    379080,
  0, 3, 5351346, 341368830
		

Crossrefs

Cf. A290516 (row sums).

Programs

  • Mathematica
    nn = 8; g[ n_] := (q - 1)^n  q^Binomial[n, 2] FunctionExpand[
        QFactorial[n, q]] /. q -> 3; G[u_, z_] := Sum[z^k/\[Gamma][k], {k, 0, nn}] - 1 + u ; Grid[Map[Reverse,Table[\[Gamma][n], {n, 0, nn}] CoefficientList[Series[G[u, z]^3, {z, 0, nn}], {z, u}]]]

Formula

T(n,k)/A053290(n) is the coefficient of y^(3-k)*x^n in the expansion of (-1 + y + Sum_{n>=0} x^n/A053290(n))^3.