A252014 Number of (n+2)X(7+2) 0..3 arrays with every 3X3 subblock row and column sum 1 3 6 or 8 and every diagonal and antidiagonal sum not 1 3 6 or 8

3246, 6562, 14450, 29954, 104034, 303906, 630978, 2189170, 6377986, 13220098, 45964930, 133947666, 277662018, 965273490, 2812900946, 5830902338, 20270743250, 59070919826, 122448949058, 425685608210, 1240489316306

Offset

1,1

Comments

Column 7 of A252015

Links

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

Formula

Empirical: a(n) = a(n-1) +21*a(n-3) -21*a(n-4) for n>15

Example

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

Crossrefs

Sequence in context: A254974 A118212 A233750 * A247725 A265198 A269061

Adjacent sequences: A252011 A252012 A252013 * A252015 A252016 A252017

Keyword

nonn

Author

R. H. Hardin, Dec 12 2014

Status

approved