A261261 Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00010101 00100101 or 01010101.

166, 232, 690, 1918, 4350, 10382, 26072, 63964, 155288, 379950, 931560, 2278454, 5570500, 13629422, 33349058, 81580648, 199570734, 488243484, 1194455224, 2922102016, 7148645416, 17488560724, 42784191822, 104667572730, 256059752954

Offset

1,1

Comments

Column 4 of A261265.

Links

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

Formula

Empirical: a(n) = a(n-1) +5*a(n-3) +4*a(n-4) +8*a(n-5) +7*a(n-6) +7*a(n-7) +5*a(n-8) -5*a(n-9) -8*a(n-10) -7*a(n-11) -5*a(n-12) -a(n-13) +a(n-14) +a(n-15) +a(n-16) for n>17

Example

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

Crossrefs

Cf. A261265.

Sequence in context: A184128 A015982 A065210 * A261288 A038007 A020361

Adjacent sequences: A261258 A261259 A261260 * A261262 A261263 A261264

Keyword

nonn

Author

R. H. Hardin, Aug 13 2015

Status

approved