A185559 T(n,k)=1/3 the number of nXk 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

0, 1, 1, 1, 5, 1, 3, 26, 26, 3, 5, 120, 224, 120, 5, 11, 576, 2530, 2530, 576, 11, 21, 2768, 25496, 58458, 25496, 2768, 21, 43, 13256, 269496, 1317540, 1317540, 269496, 13256, 43, 85, 63544, 2792166, 30132444, 64354744, 30132444, 2792166, 63544, 85, 171

Offset

1,5

Comments

Table starts

...0.......1..........1.............3.................5.................11

...1.......5.........26...........120...............576...............2768

...1......26........224..........2530.............25496.............269496

...3.....120.......2530.........58458...........1317540...........30132444

...5.....576......25496.......1317540..........64354744.........3228500154

..11....2768.....269496......30132444........3228500154.......353403366772

..21...13256....2792166.....684657326......160107914496.....38323943289566

..43...63544...29168100...15594228288.....7976049592892...4170998760222200

..85..304608..303674928..354894362166...396657534279472.453352604882802786

.171.1460072.3165976954.8078976180614.19739291980979494

Links

R. H. Hardin, Table of n, a(n) for n = 1..111

Example

Some solutions for 5X4 with a(1,1)=0
..0..0..0..0....0..0..0..0....0..0..0..1....0..0..0..1....0..0..0..1
..0..2..2..0....0..2..2..2....0..2..0..1....0..1..1..1....0..2..0..1
..1..2..0..2....1..1..1..1....0..2..1..1....0..2..2..2....0..2..2..2
..1..2..0..2....0..0..0..0....0..0..2..2....0..1..1..1....0..1..0..0
..0..0..0..2....1..1..2..2....1..1..1..2....0..2..2..1....0..1..1..1

Crossrefs

Column 1 is A001045(n-1)

Sequence in context: A143700 A036790 A201847 * A275842 A147640 A096615

Adjacent sequences: A185556 A185557 A185558 * A185560 A185561 A185562

Keyword

nonn,tabl

Author

R. H. Hardin Jan 31 2011

Status

approved