A207501 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically

9, 81, 297, 1004, 2942, 7305, 17911, 40262, 87990, 187012, 385400, 783726, 1564402, 3084097, 6019187, 11629307, 22307563, 42493220, 80468378, 151622295, 284370183, 531240776, 988874960, 1834816342, 3394683936, 6264203818, 11531988896

Offset

1,1

Comments

Row 4 of A207500

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -a(n-2) -10*a(n-3) -3*a(n-4) +28*a(n-5) +4*a(n-6) -32*a(n-7) -15*a(n-8) +26*a(n-9) +8*a(n-10) -6*a(n-11) +8*a(n-12) -4*a(n-13) -13*a(n-14) -2*a(n-15) +11*a(n-16) -2*a(n-17) +a(n-18) -2*a(n-21) +a(n-22)

Example

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

Crossrefs

Sequence in context: A207124 A207854 A207962 * A207438 A208138 A207444

Adjacent sequences: A207498 A207499 A207500 * A207502 A207503 A207504

Keyword

nonn

Author

R. H. Hardin Feb 18 2012

Status

approved