A187640 Number of (n+2)X3 0..2 arrays with each 3X3 subblock having sum 9

3139, 17701, 101419, 596653, 3703651, 23126677, 145502251, 935121589, 6025592131, 38949920557, 254629101139, 1667294249173, 10939228709659, 72317298989221, 478748984330419, 3174887984002333, 21179786460551971

Offset

1,1

Comments

Column 1 of A187645

Links

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

Formula

Empirical: a(n)=7*a(n-1)+448*a(n-3)-3136*a(n-4)-60597*a(n-6)+424179*a(n-7)+3015306*a(n-9)-21107142*a(n-10)-49152096*a(n-12)+344064672*a(n-13)+216040608*a(n-15)-1512284256*a(n-16)

Example

Some solutions for 4X3
..2..0..0....0..0..1....1..2..0....2..0..2....1..2..0....2..0..2....1..2..0
..0..2..2....2..1..1....1..1..0....0..1..0....1..2..0....2..0..0....2..2..0
..1..1..1....2..2..0....2..1..1....1..2..1....2..1..0....2..1..0....0..1..1
..0..1..1....0..0..1....0..1..2....2..0..2....1..1..1....2..2..0....1..1..1

Crossrefs

Sequence in context: A031554 A180297 A187645 * A187639 A322536 A172641

Adjacent sequences: A187637 A187638 A187639 * A187641 A187642 A187643

Keyword

nonn

Author

R. H. Hardin Mar 12 2011

Status

approved