A204734 Number of (n+1)X3 0..1 arrays with rows and columns of permanents of all 2X2 subblocks lexicographically nondecreasing, and all 2X2 permanents nonzero

15, 43, 115, 304, 787, 2033, 5219, 13398, 34331, 87991, 225395, 577452, 1479139, 3789069, 9705763, 24862194, 63685419, 163134387, 417876275, 1070414056, 2741919411, 7023575913, 17991253859, 46085557838, 118050573627, 302392805359

Offset

1,1

Comments

Column 2 of A204740

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -2*a(n-2) -8*a(n-3) +11*a(n-4) -4*a(n-5).

Empirical G.f.: x*(15-17*x-27*x^2+50*x^3-20*x^4)/((1-x)^3*(1-x-4*x^2)). [Colin Barker, Jan 19 2012]

Example

Some solutions for n=4
..1..0..1....0..1..1....1..0..1....0..1..1....0..1..1....0..1..0....1..1..0
..1..1..1....1..1..0....1..1..1....1..0..1....1..0..1....1..0..1....0..1..1
..1..1..1....0..1..1....1..0..1....1..1..1....0..1..0....1..1..1....1..0..1
..1..1..1....1..0..1....1..1..0....1..0..1....1..1..1....1..0..1....1..1..0
..1..1..1....1..1..0....1..0..1....0..1..1....1..0..1....1..1..1....0..1..1

Crossrefs

Sequence in context: A137183 A173873 A124708 * A126369 A193647 A133343

Adjacent sequences: A204731 A204732 A204733 * A204735 A204736 A204737

Keyword

nonn

Author

R. H. Hardin Jan 18 2012

Status

approved