A224547 Number of (n+1) X 6 0..1 matrices with each 2 X 2 subblock idempotent.

80, 137, 193, 294, 428, 635, 943, 1420, 2162, 3333, 5193, 8166, 12936, 20611, 32983, 52952, 85210, 137349, 221653, 357998, 578544, 935327, 1512543, 2446424, 3957398, 6402125, 10357693, 16757850, 27113432, 43869023, 70980043, 114846496

Offset: 1

Author

R. H. Hardin, Apr 10 2013

Keywords

• nonn

Comments

Column 5 of A224550.

Examples

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

Links

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

Crossrefs

Cf. A224550.

Formula

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

Empirical g.f.: x*(80 - 183*x + 45*x^2 + 127*x^3 - 80*x^4 + 6*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Aug 30 2018