A207770 Number of n X 4 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 0 vertically.

10, 100, 292, 828, 2514, 7164, 20104, 57458, 165182, 475522, 1374786, 3988072, 11586166, 33700098, 98126672, 285904744, 833354524, 2429866940, 7086585498, 20670718296, 60300595980, 175923202614, 513272786306, 1497579333338

Offset

1,1

Comments

Column 4 of A207774.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -8*a(n-2) +17*a(n-3) -46*a(n-4) +40*a(n-5) -41*a(n-6) +115*a(n-7) -38*a(n-8) +2*a(n-9) -144*a(n-10) -18*a(n-11) +52*a(n-12) +133*a(n-13) +44*a(n-14) -42*a(n-15) -86*a(n-16) -34*a(n-17) +16*a(n-18) +26*a(n-19) +16*a(n-20) -2*a(n-21) -3*a(n-22) -2*a(n-23) -a(n-24) for n>25.

Example

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

Crossrefs

Cf. A207774.

Sequence in context: A208836 A208684 A207348 * A207897 A207657 A305668

Adjacent sequences: A207767 A207768 A207769 * A207771 A207772 A207773

Keyword

nonn

Author

R. H. Hardin, Feb 20 2012

Status

approved