A184542 Number of (n+2) X 5 binary arrays with each 3 X 3 subblock having rows and columns in lexicographically nondecreasing order.

147, 340, 631, 1048, 1627, 2413, 3461, 4837, 6619, 8898, 11779, 15382, 19843, 25315, 31969, 39995, 49603, 61024, 74511, 90340, 108811, 130249, 155005, 183457, 216011, 253102, 295195, 342786, 396403, 456607, 523993, 599191, 682867, 775724, 878503

Offset

1,1

Comments

Column 3 of A184548.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = (1/120)*n^5 + (5/24)*n^4 + (49/24)*n^3 + (739/24)*n^2 + (1659/20)*n + 31.

Conjectures from Colin Barker, Apr 13 2018: (Start)

G.f.: x*(147 - 542*x + 796*x^2 - 578*x^3 + 209*x^4 - 31*x^5) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>5.

(End)

Example

Some solutions for 4 X 5:
..0..0..0..0..0....0..0..0..0..1....0..0..0..0..0....0..0..0..0..0
..0..0..0..1..1....0..0..0..0..1....0..0..0..1..1....0..0..0..0..1
..0..0..1..0..0....0..0..1..1..1....0..1..1..0..0....0..0..1..1..0
..0..0..1..1..1....0..1..1..1..1....1..1..1..1..1....0..1..1..1..0

Crossrefs

Cf. A184548.

Sequence in context: A259288 A325608 A255103 * A350638 A162701 A063701

Adjacent sequences: A184539 A184540 A184541 * A184543 A184544 A184545

Keyword

nonn

Author

R. H. Hardin, Jan 16 2011

Status

approved