A251675 Number of (n+2)X(1+2) 0..2 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 2 or 4

293, 489, 953, 2257, 5151, 12063, 29839, 72345, 176143, 435429, 1069885, 2629463, 6489171, 15986259, 39377317, 97110263, 239369633, 589963893, 1454573751, 3585822223, 8839317615, 21791873761, 53722460943, 132436498045, 326492433109

Offset

1,1

Comments

Column 1 of A251682

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +11*a(n-3) -13*a(n-4) +8*a(n-5) -32*a(n-6) +16*a(n-7) -18*a(n-8) +24*a(n-9) +20*a(n-10) +16*a(n-11) -8*a(n-12) -16*a(n-13) -8*a(n-14) for n>15

Example

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

Crossrefs

Sequence in context: A245583 A252409 A251682 * A142784 A142847 A142558

Adjacent sequences: A251672 A251673 A251674 * A251676 A251677 A251678

Keyword

nonn

Author

R. H. Hardin, Dec 06 2014

Status

approved