A208640 Number of 5 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

16, 89, 284, 722, 1652, 3577, 7504, 15448, 31440, 63543, 127884, 256718, 514556, 1030421, 2062360, 4126468, 8254936, 16512147, 33026868, 66056634, 132116516, 264236657, 528477344, 1056959152, 2113923232, 4227851887, 8455709724

Offset

1,1

Comments

Row 5 of A208637.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 14*a(n-2) + 16*a(n-3) - 9*a(n-4) + 2*a(n-5) for n>7.

Conjectures from Colin Barker, Jul 05 2018: (Start)

G.f.: x*(16 - 7*x - 26*x^2 + 8*x^3 + 16*x^4 - 2*x^5 - 4*x^6) / ((1 - x)^4*(1 - 2*x)).

a(n) = -84 + 63*2^n - (191*n)/6 - 4*n^2 - n^3/6 for n>2.

(End)

Example

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

Crossrefs

Cf. A208637.

Sequence in context: A120045 A301794 A301967 * A301888 A302084 A229399

Adjacent sequences: A208637 A208638 A208639 * A208641 A208642 A208643

Keyword

nonn

Author

R. H. Hardin, Feb 29 2012

Status

approved