A240770 Number of nX2 0..3 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..3 introduced in row major order

1, 5, 28, 196, 1418, 10314, 75138, 547557, 3990640, 29085026, 211983034, 1545021626, 11260787296, 82073558277, 598188294684, 4359860795616, 31776595508282, 231601902583978, 1688017273760974, 12303017833728109

Offset

1,2

Comments

Column 2 of A240774

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -36*a(n-2) +4*a(n-3) +51*a(n-4) +74*a(n-5) -105*a(n-6) -60*a(n-7) +22*a(n-8) +66*a(n-9) -27*a(n-10) for n>11

Example

Some solutions for n=4
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..2..3....2..3....1..2....1..0....1..2....2..0....2..2....1..0....1..0....2..3
..0..1....1..2....3..1....0..2....0..1....0..2....2..2....0..1....0..1....3..2
..1..3....3..0....2..0....2..3....3..0....2..1....0..1....2..3....1..2....1..3

Crossrefs

Sequence in context: A367049 A024065 A003467 * A318364 A064898 A368792

Adjacent sequences: A240767 A240768 A240769 * A240771 A240772 A240773

Keyword

nonn

Author

R. H. Hardin, Apr 12 2014

Status

approved