A207701 Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

25, 625, 3969, 15129, 43681, 105625, 225625, 439569, 797449, 1366561, 2235025, 3515625, 5349969, 7912969, 11417641, 16120225, 22325625, 30393169, 40742689, 53860921, 70308225, 90725625, 115842169, 146482609, 183575401, 228161025

Offset

1,1

Comments

Column 6 of A207703.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7).

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

G.f.: x*(25 + 450*x + 119*x^2 - 404*x^3 + 127*x^4 + 2*x^5 + x^6) / (1 - x)^7.

a(n) = (-3 + n + 15*n^2 + 2*n^3)^2 / 9.

(End)

Example

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

Crossrefs

Cf. A207703.

Sequence in context: A207241 A207110 A207466 * A207906 A208037 A207856

Adjacent sequences: A207698 A207699 A207700 * A207702 A207703 A207704

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved