A207962 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 0 vertically

9, 81, 297, 989, 3080, 9994, 32358, 104176, 335940, 1083914, 3495930, 11275444, 36368274, 117303034, 378351488, 1220339904, 3936101206, 12695569864, 40948497182, 132075911156, 425999751988, 1374026441136, 4431806698176

Offset

1,1

Comments

Row 4 of A207960

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) +11*a(n-3) +11*a(n-4) -a(n-5) -20*a(n-6) -27*a(n-7) -5*a(n-8) +20*a(n-9) +13*a(n-10) -3*a(n-11) -4*a(n-12) for n>15

Example

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

Crossrefs

Sequence in context: A208035 A207124 A207854 * A207501 A207438 A208138

Adjacent sequences: A207959 A207960 A207961 * A207963 A207964 A207965

Keyword

nonn

Author

R. H. Hardin Feb 21 2012

Status

approved