A252190 Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 1 3 6 or 7

7973, 9508, 13737, 21417, 37035, 57629, 87230, 150297, 239980, 380896, 661172, 1077056, 1764648, 3158368, 5312912, 9015496, 16782224, 29334608, 51772488, 100395856, 182091344, 332883016, 667871312, 1246565456, 2338093128

Offset

1,1

Comments

Column 6 of A252192

Links

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

Formula

Empirical: a(n) = 15*a(n-3) -70*a(n-6) +120*a(n-9) -64*a(n-12) for n>21

Example

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

Crossrefs

Sequence in context: A254138 A157660 A236786 * A233730 A175507 A126893

Adjacent sequences: A252187 A252188 A252189 * A252191 A252192 A252193

Keyword

nonn

Author

R. H. Hardin, Dec 15 2014

Status

approved