A224602 Number of (n+2) X 6 0..2 matrices with each 3 X 3 subblock idempotent.

416, 449, 571, 666, 906, 1247, 1657, 2280, 3216, 4533, 6443, 9258, 13358, 19335, 28093, 40916, 59680, 87165, 127435, 186430, 272870, 399539, 585161, 857180, 1255824, 1840045, 2696239, 3951030, 5789994, 8485103, 12434953, 18223716

Offset

1,1

Comments

Column 4 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*(416 - 1215*x + 1271*x^2 - 1004*x^3 + 1087*x^4 - 688*x^5 + 128*x^6 + 4*x^7) / ((1 - x)^3*(1 - x - x^3)). - Colin Barker, Sep 01 2018

Example

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

Crossrefs

Cf. A224606.

Sequence in context: A306381 A172779 A056068 * A249006 A249471 A246897

Adjacent sequences: A224599 A224600 A224601 * A224603 A224604 A224605

Keyword

nonn

Author

R. H. Hardin, Apr 11 2013

Status

approved