

A199142


Number of nX1 0..3 arrays with values 0..3 introduced in row major order and each element equal to one or two horizontal and vertical neighbors


3



0, 1, 1, 2, 3, 6, 11, 23, 47, 102, 221, 492, 1099, 2485, 5637, 12858, 29391, 67354, 154539, 355003, 816035, 1876862, 4318201, 9937840, 22874731, 52659593, 121237417, 279141170, 642732027, 1479959118, 3407837387, 7847200511
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OFFSET

1,4


COMMENTS

Column 1 of A199149


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200


FORMULA

Empirical: a(n) = 3*a(n1) +a(n2) 7*a(n3) +a(n4) +3*a(n5) for n>6


EXAMPLE

Some solutions for n=8
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....0....0....1....1....1....0....1....1....0....1....0....0....0....1....0
..1....1....0....1....1....1....1....1....1....0....1....0....0....0....1....0
..2....1....1....1....1....0....1....2....1....0....2....1....0....1....1....0
..2....1....1....0....2....0....0....2....1....1....2....1....0....1....1....0
..2....0....0....0....2....1....0....1....0....1....3....1....0....2....2....1
..2....0....0....0....2....1....0....1....0....1....3....1....0....2....2....1


CROSSREFS

Sequence in context: A036656 A001190 A274937 * A090344 A277795 A198662
Adjacent sequences: A199139 A199140 A199141 * A199143 A199144 A199145


KEYWORD

nonn


AUTHOR

R. H. Hardin Nov 03 2011


STATUS

approved



