A207700 Number of n X 5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

15, 225, 1071, 3321, 8151, 17225, 32775, 57681, 95551, 150801, 228735, 335625, 478791, 666681, 908951, 1216545, 1601775, 2078401, 2661711, 3368601, 4217655, 5229225, 6425511, 7830641, 9470751, 11374065, 13570975, 16094121, 18978471

Offset

1,1

Comments

Column 5 of A207703.

Links

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

Formula

Empirical: 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).

Conjectures from Colin Barker, Jun 25 2018: (Start)

G.f.: x*(15 + 135*x - 54*x^2 - 30*x^3 + 15*x^4 - x^5) / (1 - x)^6.

a(n) = (3 - 10*n - 15*n^2 + 44*n^3 + 21*n^4 + 2*n^5) / 3.

(End)

Example

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

Crossrefs

Cf. A207703.

Sequence in context: A207596 A208115 A267784 * A207905 A208036 A207855

Adjacent sequences: A207697 A207698 A207699 * A207701 A207702 A207703

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved