A208779 Number of n X 7 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 1 vertically.

42, 1764, 252, 420, 672, 1092, 1764, 2856, 4620, 7476, 12096, 19572, 31668, 51240, 82908, 134148, 217056, 351204, 568260, 919464, 1487724, 2407188, 3894912, 6302100, 10197012, 16499112, 26696124, 43195236, 69891360, 113086596

Offset

1,1

Comments

Column 7 of A208780.

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-2) for n>4.

Empirical g.f.: 42*x*(1 + 41*x - 37*x^2 - 38*x^3) / (1 - x - x^2). - Colin Barker, Jul 06 2018

Example

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

Crossrefs

Cf. A208780.

Sequence in context: A170761 A218744 A158727 * A208500 A207588 A207844

Adjacent sequences: A208776 A208777 A208778 * A208780 A208781 A208782

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved