A251676 Number of (n+2)X(2+2) 0..2 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 2 or 4

489, 865, 2089, 5065, 13031, 36075, 100307, 282489, 805963, 2300981, 6582921, 18872307, 54105547, 155166259, 445147549, 1277038995, 3663729245, 10511626757, 30158791311, 86528621567, 248262408987, 712297721821, 2043676016379

Offset

1,1

Comments

Column 2 of A251682

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -a(n-2) +12*a(n-3) -29*a(n-4) +a(n-5) -36*a(n-6) +82*a(n-7) +17*a(n-8) +26*a(n-9) -56*a(n-10) -20*a(n-11) -18*a(n-12) -37*a(n-13) -39*a(n-14) +20*a(n-15) +52*a(n-16) +52*a(n-17) +12*a(n-18) -20*a(n-19) -12*a(n-20) -8*a(n-21) for n>22

Example

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

Crossrefs

Sequence in context: A201835 A201215 A214807 * A230005 A221940 A221739

Adjacent sequences: A251673 A251674 A251675 * A251677 A251678 A251679

Keyword

nonn

Author

R. H. Hardin, Dec 06 2014

Status

approved