A260973 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00001001 or 00100101.

48, 91, 204, 483, 1146, 2755, 6526, 15419, 36518, 86831, 206258, 489087, 1159490, 2751195, 6530006, 15494419, 36755918, 87199191, 206899498, 490917751, 1164739402, 2763371171, 6556331950, 15555736875, 36907711926, 87566685887

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) - 2*a(n-2) + 4*a(n-3) + 3*a(n-4) + 6*a(n-5) + 4*a(n-6) + 16*a(n-8) for n>9.

Empirical g.f.: x*(48 - 5*x + 118*x^2 + 65*x^3 + 80*x^4 + 52*x^5 + 26*x^6 + 256*x^7 - 208*x^8) / (1 - 2*x + 2*x^2 - 4*x^3 - 3*x^4 - 6*x^5 - 4*x^6 - 16*x^8). - Colin Barker, Dec 29 2018

Example

Some solutions for n=4:
..0..0..1....0..1..0....0..0..0....0..0..1....0..1..0....0..0..0....0..1..0
..1..0..0....0..0..1....0..1..0....1..0..0....0..1..0....0..0..1....0..1..0
..0..0..1....1..0..0....0..1..0....0..0..0....0..0..1....1..0..0....1..0..0
..0..1..0....0..0..1....0..0..0....0..0..0....1..0..0....0..0..1....0..0..1
..0..0..0....0..0..0....1..0..0....1..0..0....0..0..1....1..0..0....0..0..0
..1..0..1....0..0..0....0..0..1....0..0..1....0..0..0....0..1..0....0..1..0

Crossrefs

Column 1 of A260980.

Sequence in context: A204647 A260980 A260070 * A260063 A211723 A274899

Adjacent sequences: A260970 A260971 A260972 * A260974 A260975 A260976

Keyword

nonn

Author

R. H. Hardin, Aug 06 2015

Status

approved