A252274 Number of (n+2)X(4+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 2 3 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 2 3 4 6 or 7

322, 948, 2513, 4895, 15739, 43488, 85808, 276544, 765830, 1513196, 4875644, 13503569, 26685485, 85977789, 238124824, 470585534, 1516162514, 4199176596, 8298487316, 26736562424, 74049808021, 146338582343, 471482312899

Offset

1,1

Comments

Column 4 of A252278

Links

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

Formula

Empirical: a(n) = 21*a(n-3) -62*a(n-6) +47*a(n-9) -5*a(n-12) for n>15

Example

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

Crossrefs

Sequence in context: A004947 A004967 A251231 * A114358 A158305 A237406

Adjacent sequences: A252271 A252272 A252273 * A252275 A252276 A252277

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved