A252633 Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 4 6 or 7

572, 687, 1189, 2230, 4382, 8697, 17046, 34424, 69196, 136906, 278002, 561138, 1119260, 2283480, 4624958, 9291788, 19034708, 38667770, 78183568, 160738190, 327379782, 665660970, 1372806636, 2802341926, 5725582074, 11839463788

Offset

1,1

Comments

Column 1 of A252640

Links

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

Formula

Empirical: a(n) = 25*a(n-3) -222*a(n-6) +815*a(n-9) -1085*a(n-12) +696*a(n-15) -756*a(n-18) for n>24

Example

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

Crossrefs

Sequence in context: A144956 A178323 A049361 * A175989 A252640 A252641

Adjacent sequences: A252630 A252631 A252632 * A252634 A252635 A252636

Keyword

nonn

Author

R. H. Hardin, Dec 19 2014

Status

approved