A224557 Number of (n+2) X 8 0..1 matrices with each 3 X 3 subblock idempotent.

418, 351, 451, 551, 740, 992, 1298, 1742, 2382, 3267, 4530, 6362, 9003, 12826, 18395, 26514, 38360, 55674, 81001, 118063, 172323, 251789, 368191, 538722, 788583, 1154705, 1691212, 2477429, 3629612, 5318141, 7792721, 11419313, 16734258

Offset

1,1

Comments

Column 6 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*(418 - 1321*x + 1555*x^2 - 1237*x^3 + 1159*x^4 - 767*x^5 + 184*x^6 + 4*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Aug 31 2018

Example

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

Crossrefs

Cf. A224559.

Sequence in context: A239191 A324613 A202527 * A292422 A328497 A138062

Adjacent sequences: A224554 A224555 A224556 * A224558 A224559 A224560

Keyword

nonn

Author

R. H. Hardin, Apr 10 2013

Status

approved