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

1,1

Comments

Column 4 of A261380.

Links

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

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

Example

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

Crossrefs

Cf. A261380.

Sequence in context: A142528 A139500 A344481 * A142094 A142212 A108655

Adjacent sequences: A261373 A261374 A261375 * A261377 A261378 A261379

Keyword

nonn

Author

R. H. Hardin, Aug 17 2015

Status

approved