A224556 Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent.

263, 246, 320, 395, 540, 740, 988, 1351, 1881, 2623, 3689, 5243, 7494, 10763, 15535, 22504, 32685, 47578, 69377, 101291, 148029, 216494, 316798, 463762, 679110, 994678, 1457123, 2134826, 3128004, 4583531, 6716662, 9842869, 14424498

Offset

1,1

Comments

Column 5 of A224559.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

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

Empirical g.f.: x*(263 - 806*x + 914*x^2 - 724*x^3 + 702*x^4 - 455*x^5 + 98*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Aug 31 2018

Example

Some solutions for n=3:
..1..1..1..0..0..0..0....1..1..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..0....0..0..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....1..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....0..0..0..0..0..0..0
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....1..0..0..0..1..1..1

Crossrefs

Cf. A224559.

Sequence in context: A264972 A241877 A270752 * A052033 A105008 A345577

Adjacent sequences: A224553 A224554 A224555 * A224557 A224558 A224559

Keyword

nonn

Author

R. H. Hardin, Apr 10 2013

Status

approved