A260602 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101.

40, 58, 125, 241, 525, 1029, 2246, 4407, 9592, 18930, 41027, 81192, 175502, 348438, 750714, 1494859, 3211981, 6412772, 13742956, 27507848, 58807987, 117983491, 251666242, 506004675, 1077074116, 2169965427, 4609962160, 9305093538

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) - a(n-3) + 7*a(n-4) - 10*a(n-5) + 6*a(n-6) - 5*a(n-7) - 3*a(n-8) + 6*a(n-9) + 2*a(n-10) - 8*a(n-11) + 4*a(n-12) for n>13.

Empirical g.f.: x*(40 + 18*x - 13*x^2 + 40*x^3 - 188*x^4 + 141*x^5 - 127*x^6 + 43*x^7 + 117*x^8 - 70*x^9 - 110*x^10 + 136*x^11 - 36*x^12) / ((1 - x)*(1 - 2*x^2 - x^3 - 8*x^4 + 2*x^5 - 4*x^6 + x^7 + 4*x^8 - 2*x^9 - 4*x^10 + 4*x^11)). - Colin Barker, Dec 29 2018

Example

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

Crossrefs

Column 1 of A260609.

Sequence in context: A349242 A369150 A260609 * A116309 A126816 A361623

Adjacent sequences: A260599 A260600 A260601 * A260603 A260604 A260605

Keyword

nonn

Author

R. H. Hardin, Jul 29 2015

Status

approved