A163047 Number of n X 3 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, 6911489174731816, 34948767025722701

Offset

1,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (7,-11,6,1,-7,1).

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). - 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). - R. J. Mathar, Aug 11 2009

Crossrefs

Column 3 of A389687.

Sequence in context: A122677 A038177 A389891 * A369616 A372378 A369594

Adjacent sequences: A163044 A163045 A163046 * A163048 A163049 A163050

Keyword

nonn,easy

Author

R. H. Hardin, Jul 20 2009

Status

approved