A259737 Number of (n+2) X (3+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 or 01010101.

42, 74, 190, 374, 792, 1514, 3480, 6542, 14580, 27866, 62700, 118718, 266548, 506810, 1138004, 2160350, 4852180, 9215834, 20694708, 39301214, 88262564, 167620346, 376424388, 714880094, 1605429620, 3048894554, 6846969460, 13003247390

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-2) + 9*a(n-4) + 4*a(n-6) - 6*a(n-8) + 4*a(n-10) for n>11.

Empirical g.f.: 2*x*(21 + 37*x + 53*x^2 + 113*x^3 + 17*x^4 + 50*x^5 + 9*x^6 - 74*x^7 - 8*x^8 + 52*x^9 + 12*x^10) / (1 - 2*x^2 - 9*x^4 - 4*x^6 + 6*x^8 - 4*x^10). - Colin Barker, Dec 26 2018

Example

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

Crossrefs

Column 3 of A259742.

Sequence in context: A043752 A043760 A043769 * A039525 A072326 A068700

Adjacent sequences: A259734 A259735 A259736 * A259738 A259739 A259740

Keyword

nonn

Author

R. H. Hardin, Jul 04 2015

Status

approved