A196140 Number of nX2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,0,4,1,2 for x=0,1,2,3,4

3, 5, 8, 17, 34, 62, 123, 243, 471, 924, 1817, 3558, 6978, 13697, 26865, 52699, 103398, 202847, 397944, 780720, 1531657, 3004865, 5895113, 11565346, 22689467, 44513380, 87328672, 171325871, 336115955, 659409701, 1293664016, 2537976953, 4979134498

Offset

1,1

Comments

Every 0 is next to 0 3's, every 1 is next to 1 0's, every 2 is next to 2 4's, every 3 is next to 3 1's, every 4 is next to 4 2's

Column 2 of A196146

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-3) -2*a(n-4) -a(n-5) +a(n-6)

Example

Some solutions for n=4
.1.0...0.1...1.0...0.0...0.1...1.0...1.0...1.0...0.0...1.1
.1.0...1.3...3.1...0.0...0.1...1.1...1.0...3.1...1.1...0.0
.1.1...3.1...1.1...0.0...1.1...0.1...1.0...1.3...1.1...0.0
.0.1...1.0...0.0...1.1...1.0...0.1...1.0...0.1...0.0...0.0

Crossrefs

Sequence in context: A291223 A240532 A184434 * A336016 A240154 A376785

Adjacent sequences: A196137 A196138 A196139 * A196141 A196142 A196143

Keyword

nonn

Author

R. H. Hardin Sep 28 2011

Status

approved