A261286 Number of (n+2)X(2+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00010101 or 01010101.

50, 77, 133, 233, 409, 743, 1361, 2469, 4485, 8183, 14901, 27091, 49293, 89729, 163277, 297055, 540549, 983737, 1790089, 3257319, 5927571, 10786801, 19628869, 35719195, 65000021, 118283183, 215243755, 391687275, 712769639, 1297054417

Offset

1,1

Comments

Column 2 of A261292.

Links

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

Formula

Empirical: a(n) = a(n-1) +4*a(n-3) -a(n-4) -5*a(n-6) +2*a(n-8) +a(n-9) -a(n-10) -3*a(n-11) +a(n-12) +a(n-13) +a(n-14) -2*a(n-15) -2*a(n-16) for n>17

Example

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

Crossrefs

Cf. A261292.

Sequence in context: A071366 A321517 A045165 * A259670 A138381 A349208

Adjacent sequences: A261283 A261284 A261285 * A261287 A261288 A261289

Keyword

nonn

Author

R. H. Hardin, Aug 14 2015

Status

approved