A252539 Number of (7+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7.

823, 1344, 2332, 3160, 10720, 18656, 25280, 85760, 149248, 202240, 686080, 1193984, 1617920, 5488640, 9551872, 12943360, 43909120, 76414976, 103546880, 351272960, 611319808, 828375040, 2810183680, 4890558464, 6627000320, 22481469440

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-3) for n>5.

Empirical g.f.: x*(823 + 1344*x + 2332*x^2 - 3424*x^3 - 32*x^4) / ((1 - 2*x)*(1 + 2*x + 4*x^2)). - Colin Barker, Dec 05 2018

Example

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

Crossrefs

Row 7 of A252532.

Sequence in context: A364538 A326817 A271044 * A033531 A088360 A057002

Adjacent sequences: A252536 A252537 A252538 * A252540 A252541 A252542

Keyword

nonn

Author

R. H. Hardin, Dec 18 2014

Status

approved