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A261286
Number of (n+2)X(2+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00010101 or 01010101.
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 14 2015
STATUS
approved