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A261373
Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101.
1
36, 39, 60, 97, 154, 247, 392, 618, 977, 1548, 2461, 3894, 6176, 9774, 15513, 24552, 38963, 61662, 97854, 154866, 245769, 388956, 617257, 976878, 1550272, 2453478, 3893581, 6162024, 9778911, 15476214, 24560198, 38869242, 61684093, 97621932
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-2) + 3*a(n-4) + 2*a(n-6) for n>12.
Empirical g.f.: x*(36 + 39*x + 24*x^2 + 58*x^3 - 14*x^4 + 33*x^5 - 14*x^6 + 2*x^7 + 3*x^8 - 5*x^9 - 2*x^11) / (1 - x^2 - 3*x^4 - 2*x^6). - Colin Barker, Dec 30 2018
EXAMPLE
Some solutions for n=4:
0 1 0 1 0 0 1 0 1 1 0 0 0 1 0 1 0 1 1 0 1
1 0 0 1 0 0 0 0 1 0 1 0 1 0 1 0 0 1 0 1 0
0 1 0 0 1 0 0 0 0 1 0 1 0 1 0 0 0 0 0 0 1
1 0 1 1 0 1 0 1 1 0 1 0 1 0 1 1 0 1 0 1 0
0 1 0 0 1 0 1 1 0 1 0 0 0 0 0 0 1 0 1 0 1
0 0 1 1 0 1 0 0 0 0 1 0 0 0 1 1 0 0 0 0 0
CROSSREFS
Column 1 of A261380.
Sequence in context: A181457 A261380 A337861 * A248372 A349705 A129288
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 17 2015
STATUS
approved