A224603 Number of (n+2) X 7 0..2 matrices with each 3 X 3 subblock idempotent.

628, 630, 782, 906, 1202, 1609, 2091, 2817, 3895, 5397, 7564, 10745, 15361, 22074, 31895, 46256, 67251, 97985, 142995, 208912, 305472, 446948, 654244, 958000, 1403129, 2055448, 3011414, 4412397, 6465584, 9474619, 13884516, 20347476

Offset

1,1

Comments

Column 5 of A224606.

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*(628 - 1882*x + 2030*x^2 - 1582*x^3 + 1632*x^4 - 1037*x^5 + 203*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Sep 01 2018

Example

Some solutions for n=3:
..1..1..1..0..0..0..0....1..0..0..0..0..0..0....0..1..0..0..0..0..0
..0..0..0..0..0..0..0....1..0..0..0..0..0..0....0..1..0..0..0..0..1
..0..0..0..0..0..0..0....1..0..0..0..0..0..0....0..1..0..0..0..0..1
..0..0..0..0..0..0..1....2..0..0..0..0..0..0....0..1..0..0..0..0..1
..0..0..0..0..0..0..1....0..0..0..0..1..1..1....0..2..0..0..0..0..1

Crossrefs

Cf. A224606.

Sequence in context: A158382 A188362 A098260 * A345536 A345788 A261708

Adjacent sequences: A224600 A224601 A224602 * A224604 A224605 A224606

Keyword

nonn

Author

R. H. Hardin, Apr 11 2013

Status

approved