A252390 Number of (6+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 3 5 6 or 7.

904, 764, 984, 1097, 1667, 2356, 2769, 4222, 5992, 7136, 10911, 15524, 18561, 28419, 40483, 48469, 74254, 105828, 126768, 194251, 276904, 331757, 508407, 724787, 868425, 1330878, 1897360, 2273440, 3484135, 4967196, 5951817, 9121435, 13004131

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-3) - 4*a(n-6) + a(n-9) for n>15.

Empirical g.f.: x*(904 + 764*x + 984*x^2 - 2519*x^3 - 1389*x^4 - 1580*x^5 + 1997*x^6 + 610*x^7 + 504*x^8 - 456*x^9 - 73*x^10 - 4*x^11 - 4*x^12 - 4*x^13 - x^14) / ((1 - x)*(1 + x + x^2)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 03 2018

Example

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

Crossrefs

Row 6 of A252384.

Sequence in context: A284744 A111042 A115496 * A218158 A249706 A098237

Adjacent sequences: A252387 A252388 A252389 * A252391 A252392 A252393

Keyword

nonn

Author

R. H. Hardin, Dec 17 2014

Status

approved