A204477 Number of (n+2)X4 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..3 introduced in row major order

307, 1326, 3147, 2745, 8114, 29959, 111707, 425010, 1602835, 6076455, 23038228, 87322215, 331059861, 1255146516, 4758551951, 18041027869, 68398734846, 259319077335, 983153218535, 3727416848414, 14131709526987, 53577378404731

Offset

1,1

Comments

Column 2 of A204483

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +a(n-2) -2*a(n-3) -19*a(n-4) -4*a(n-5) +21*a(n-6) +24*a(n-7) +3*a(n-8) -18*a(n-9) -9*a(n-10) for n>13

Example

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

Crossrefs

Sequence in context: A125252 A308785 A142572 * A176091 A359640 A118284

Adjacent sequences: A204474 A204475 A204476 * A204478 A204479 A204480

Keyword

nonn

Author

R. H. Hardin Jan 15 2012

Status

approved