A207023 Number of nX7 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically

25, 625, 3025, 9450, 23400, 49925, 95900, 170300, 284475, 452425, 691075, 1020550, 1464450, 2050125, 2808950, 3776600, 4993325, 6504225, 8359525, 10614850, 13331500, 16576725, 20424000, 24953300, 30251375, 36412025, 43536375, 51733150

Offset

1,1

Comments

Column 7 of A207024

Links

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

Formula

Empirical: a(n) = (55/24)*n^5 + (75/4)*n^4 + (275/8)*n^3 + (75/4)*n^2 - (295/6)*n.

Empirical G.f.: 25*x*(1+19*x-14*x^2+7*x^3-2*x^4)/(1-x)^6. [Colin Barker, May 22 2012]

Example

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

Crossrefs

Sequence in context: A208424 A207784 A207597 * A208116 A207367 A207499

Adjacent sequences: A207020 A207021 A207022 * A207024 A207025 A207026

Keyword

nonn

Author

R. H. Hardin Feb 14 2012

Status

approved