A261376 Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101.

97, 157, 424, 1040, 2282, 5254, 12500, 28885, 66332, 154413, 358786, 830309, 1923846, 4465820, 10349526, 23993883, 55620850, 129004265, 298983410, 693371845, 1607151330, 3727183505, 8638778942, 20034575762, 46436324264

Offset: 1

Author

R. H. Hardin, Aug 17 2015

Keywords

• nonn

Comments

Column 4 of A261380.

Examples

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

Links

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

Crossrefs

Cf. A261380.

Formula

Empirical: a(n) = a(n-2) +18*a(n-4) +32*a(n-6) -7*a(n-8) -33*a(n-10) +13*a(n-12) +25*a(n-14) -28*a(n-16) +9*a(n-18) -a(n-20) for n>22