A207400 Number of n X 5 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.

12, 144, 612, 1782, 4212, 8692, 16284, 28362, 46652, 73272, 110772, 162174, 231012, 321372, 437932, 586002, 771564, 1001312, 1282692, 1623942, 2034132, 2523204, 3102012, 3782362, 4577052, 5499912, 6565844, 7790862, 9192132, 10788012

Offset

1,1

Comments

Column 5 of A207403.

Links

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

Formula

Empirical: a(n) = (1/3)*n^5 + 3*n^4 + (28/3)*n^3 + 7*n^2 - (29/3)*n + 2.

Conjectures from Colin Barker, Jun 22 2018: (Start)

G.f.: 2*x*(6 + 36*x - 36*x^2 + 15*x^3 - 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>6.

(End)

Example

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

Crossrefs

Cf. A207403.

Sequence in context: A207115 A207395 A207942 * A207749 A207125 A207946

Adjacent sequences: A207397 A207398 A207399 * A207401 A207402 A207403

Keyword

nonn

Author

R. H. Hardin, Feb 17 2012

Status

approved