A163047 Number of nX3 binary arrays with all 1s connected, and all corners 1

1, 3, 12, 58, 293, 1481, 7484, 37832, 191285, 967235, 4890912, 24731434, 125057361, 632367297, 3197640264, 16169248032, 81761725337, 413437887795, 2090597850596, 10571356673930, 53455322317101, 270303194968521, 1366820253696484

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..100

Formula

For n>6, a(n) = 7*a(n-1) - 11*a(n-2) + 6*a(n-3) + a(n-4) - 7*a(n-5) + a(n-6). [From Max Alekseyev, Aug 01 2009]

G.f.: -x*(x-1)*(x^2+3*x-1)/(-1+7*x-11*x^2+6*x^3+x^4-7*x^5+x^6). [From R. J. Mathar, Aug 11 2009]

Crossrefs

Sequence in context: A079245 A122677 A038177 * A369616 A372378 A369594

Adjacent sequences: A163044 A163045 A163046 * A163048 A163049 A163050

Keyword

nonn

Author

R. H. Hardin Jul 20 2009

Status

approved