login
A297301
Number of 4 X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 2 neighboring 1s.
1
1, 1, 5, 10, 21, 50, 130, 332, 840, 2128, 5408, 13772, 35102, 89465, 227961, 580788, 1479748, 3770356, 9606981, 24478804, 62372090, 158923930, 404938148, 1031783666, 2628989168, 6698674670, 17068245866, 43489945955, 110812526805
OFFSET
1,3
COMMENTS
Row 4 of A297299.
FORMULA
Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 7*a(n-3) - 4*a(n-4) + 3*a(n-5) + a(n-6) - 5*a(n-7) + 4*a(n-8) - 2*a(n-9) - a(n-10) - 5*a(n-12) - 3*a(n-13) for n > 16.
Formula verified by Robert Israel, May 25 2018: see link.
EXAMPLE
Some solutions for n=5:
0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 1 0 0
0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 1 0 0 0
0 0 1 1 0 0 0 0 1 1 1 1 0 1 0 0 0 0 1 1
0 1 1 0 0 0 0 1 1 0 1 1 1 0 0 0 0 1 1 0
CROSSREFS
Cf. A297299.
Sequence in context: A372054 A295952 A132174 * A132461 A255150 A266580
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 27 2017
STATUS
approved