A183327 Number of n X 6 binary arrays with each 1 adjacent to exactly two other 1's.

1, 9, 37, 179, 996, 4740, 21259, 96524, 443793, 2054180, 9533062, 44194763, 204545507, 946059367, 4375861741, 20244334715, 93671407936, 433436316256, 2005547859261, 9279593479796, 42935853340895, 198660544800120

Offset

1,2

Comments

Column 6 of A183328.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=7*a(n-1)-18*a(n-2)+38*a(n-3)-48*a(n-4)+110*a(n-5)-30*a(n-6)+13*a(n-7)+12*a(n-8)-168*a(n-9)+12*a(n-10)+396*a(n-11)+2076*a(n-12)-2107*a(n-13)-11936*a(n-14)-23630*a(n-15)-11374*a(n-16)+33929*a(n-17)+86596*a(n-18)+85928*a(n-19)-5767*a(n-20)-137160*a(n-21)-186375*a(n-22)-82400*a(n-23)+98660*a(n-24)+206026*a(n-25)+154539*a(n-26)+271*a(n-27)-129682*a(n-28)-144333*a(n-29)-59907*a(n-30)+31467*a(n-31)+61883*a(n-32)+37532*a(n-33)+5039*a(n-34)-7723*a(n-35)-5583*a(n-36)-944*a(n-37)+520*a(n-38)+332*a(n-39)+24*a(n-40)-32*a(n-41).

Example

Some solutions for 4 X 6
..0..1..1..1..1..1....0..0..0..0..0..0....0..1..1..1..1..1....0..1..1..1..1..0
..0..1..0..0..0..1....0..0..0..1..1..1....0..1..0..0..0..1....1..1..0..0..1..1
..0..1..1..0..0..1....0..0..0..1..0..1....0..1..0..0..1..1....1..0..0..0..0..1
..0..0..1..1..1..1....0..0..0..1..1..1....0..1..1..1..1..0....1..1..1..1..1..1

Crossrefs

Cf. A183328.

Sequence in context: A246315 A232250 A201441 * A364700 A199894 A232258

Adjacent sequences: A183324 A183325 A183326 * A183328 A183329 A183330

Keyword

nonn

Author

R. H. Hardin, Jan 03 2011

Status

approved