A224724 Number of (n+3) X 7 0..2 matrices with each 4 X 4 subblock idempotent.

3506, 2863, 3502, 3924, 4209, 5371, 7132, 9238, 11551, 14945, 20018, 27116, 36445, 49083, 66708, 91346, 125227, 171657, 235622, 324136, 446441, 615083, 847596, 1168530, 1611675, 2223365, 3067470, 4232412, 5840401, 8059979, 11123560

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..194

Formula

Empirical: a(n) = 4*a(n-1) - 7*a(n-2) + 8*a(n-3) - 6*a(n-4) + a(n-5) + 3*a(n-6) - 4*a(n-7) + 3*a(n-8) - a(n-9) for n>11.

Empirical g.f.: x*(3506 - 11161*x + 16592*x^2 - 18091*x^3 + 11159*x^4 + 1659*x^5 - 8650*x^6 + 10112*x^7 - 6687*x^8 + 1521*x^9 + 38*x^10) / ((1 - x)^3*(1 + x^2)*(1 - x - x^4)). - Colin Barker, Sep 04 2018

Example

Some solutions for n=2:
..1..0..0..0..0..0..2....1..0..0..0..0..0..0....1..0..0..0..0..0..1
..1..0..0..0..0..0..1....1..0..0..0..0..0..0....1..0..0..0..0..0..0
..1..0..0..0..0..0..1....0..0..0..0..0..0..0....1..0..0..0..0..0..1
..1..0..0..0..0..0..1....0..0..0..0..0..0..0....0..0..0..0..0..0..1
..2..0..0..0..0..0..1....0..0..2..1..1..1..1....0..0..0..0..0..0..1

Crossrefs

Column 4 of A224728.

Sequence in context: A233992 A203845 A257316 * A338978 A274237 A053804

Adjacent sequences: A224721 A224722 A224723 * A224725 A224726 A224727

Keyword

nonn

Author

R. H. Hardin, Apr 16 2013

Status

approved