A252263 Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 2 3 4 6 or 7.

130, 272, 822, 2290, 6164, 17008, 47094, 129530, 356572, 982904, 2707976, 7459326, 20550724, 56618068, 155978958, 429715562, 1183856500, 3261484928, 8985276082, 24754144796, 68196859814, 187880079930, 517603410590, 1425980330978

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) + 6*a(n-3) + 5*a(n-4) + a(n-5) - 2*a(n-6) - 2*a(n-7) - a(n-8) for n>9.

Empirical g.f.: 2*x*(65 + 71*x + 145*x^2 + 72*x^3 - 26*x^4 - 79*x^5 - 52*x^6 - 16*x^7 + 7*x^8) / (1 - x - 2*x^2 - 6*x^3 - 5*x^4 - x^5 + 2*x^6 + 2*x^7 + x^8). - Colin Barker, Dec 03 2018

Example

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

Crossrefs

Column 2 of A252269.

Sequence in context: A350195 A064687 A238194 * A252361 A252082 A253044

Adjacent sequences: A252260 A252261 A252262 * A252264 A252265 A252266

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved