A207496 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically

9, 81, 283, 1004, 3939, 15495, 62530, 253747, 1040401, 4290258, 17800079, 74193193, 310541536, 1304248843, 5493846571, 23198279836, 98159361513, 416061031363, 1766079438934, 7505644908143, 31930399614415, 135952464116764

Offset

1,1

Comments

Column 4 of A207500

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -11*a(n-2) -92*a(n-3) +184*a(n-4) +391*a(n-5) -806*a(n-6) -893*a(n-7) +1570*a(n-8) +1170*a(n-9) -1486*a(n-10) -867*a(n-11) +679*a(n-12) +340*a(n-13) -139*a(n-14) -62*a(n-15) +10*a(n-16) +4*a(n-17) for n>18

Example

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

Crossrefs

Sequence in context: A208160 A207956 A207238 * A208165 A207244 A207064

Adjacent sequences: A207493 A207494 A207495 * A207497 A207498 A207499

Keyword

nonn

Author

R. H. Hardin Feb 18 2012

Status

approved