A207597 Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.

25, 625, 3025, 9025, 21025, 42025, 75625, 126025, 198025, 297025, 429025, 600625, 819025, 1092025, 1428025, 1836025, 2325625, 2907025, 3591025, 4389025, 5313025, 6375625, 7590025, 8970025, 10530025, 12285025, 14250625, 16443025, 18879025

Offset

1,1

Comments

Column 6 of A207599.

Links

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

Formula

Empirical: a(n) = 25*n^4 + 50*n^3 - 25*n^2 - 50*n + 25.

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

G.f.: 25*x*(1 + 20*x + 6*x^2 - 4*x^3 + x^4) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.

(End)

Example

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

Crossrefs

Cf. A207599.

Sequence in context: A207912 A208424 A207784 * A207023 A208116 A207367

Adjacent sequences: A207594 A207595 A207596 * A207598 A207599 A207600

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved