A224723 Number of (n+3) X 6 0..2 matrices with each 4 X 4 subblock idempotent.

2471, 2493, 3092, 3502, 3775, 4868, 6540, 8551, 10761, 13991, 18817, 25579, 34473, 46520, 63313, 86789, 119077, 163331, 224294, 308650, 425208, 585935, 807537, 1113408, 1535747, 2118724, 2923211, 4033478, 5565990, 7681386, 10601173

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 4*a(n-4) - 3*a(n-5) + 2*a(n-7) - a(n-8) for n>10.

Empirical g.f.: x*(2471 - 4920*x + 555*x^2 + 4154*x^3 - 5445*x^4 + 4172*x^5 + 1601*x^6 - 3457*x^7 + 815*x^8 + 52*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - Colin Barker, Sep 04 2018

Example

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

Crossrefs

Column 3 of A224728.

Sequence in context: A253355 A204614 A204798 * A183703 A282559 A278733

Adjacent sequences: A224720 A224721 A224722 * A224724 A224725 A224726

Keyword

nonn

Author

R. H. Hardin, Apr 16 2013

Status

approved