A252363 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 1 3 4 6 or 7.

152, 276, 834, 2338, 6298, 17340, 48034, 132168, 363764, 1002682, 2762622, 7609830, 20965108, 57759930, 159125020, 438382240, 1207732858, 3327264630, 9166496318, 25253399040, 69572290978, 191669348524, 528042715724, 1454740272942

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*(76 + 62*x + 127*x^2 + 20*x^3 - 62*x^4 - 85*x^5 - 36*x^6 - x^7 + 16*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..2..0..0....0..0..0..0....3..3..3..3....0..2..0..0....3..3..2..3
..2..0..0..0....0..2..0..0....3..3..3..2....0..0..0..0....3..3..3..2
..0..0..0..0....0..0..0..2....3..3..3..3....0..0..0..0....3..3..3..3
..0..0..0..0....0..0..0..0....3..3..2..3....0..0..0..0....3..3..2..3
..0..2..0..0....2..0..0..0....2..3..3..3....2..0..0..2....3..3..3..3
..0..0..0..2....0..0..0..0....3..3..3..3....0..0..2..0....3..3..3..3

Crossrefs

Column 2 of A252369.

Sequence in context: A097640 A253367 A253360 * A248816 A038857 A137632

Adjacent sequences: A252360 A252361 A252362 * A252364 A252365 A252366

Keyword

nonn

Author

R. H. Hardin, Dec 17 2014

Status

approved