A252391 Number of (7+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.

1051, 903, 1114, 1361, 2031, 2778, 3495, 5195, 7123, 9045, 13466, 18506, 23568, 35117, 48310, 61587, 91799, 126339, 161121, 240194, 330622, 421704, 628697, 865442, 1103919, 1645811, 2265619, 2889981, 4308650, 5931330, 7565952, 11280053

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>14.

Empirical g.f.: x*(1051 + 903*x + 1114*x^2 - 2843*x^3 - 1581*x^4 - 1678*x^5 + 2255*x^6 + 683*x^7 + 467*x^8 - 542*x^9 - 93*x^10 + 12*x^11 + 7*x^12 + 2*x^13) / ((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..0....3..1..2..0..1..2....3..2..1..3..2..1....3..0..0..0..0..3
..0..0..0..0..0..0....1..0..2..1..0..2....0..0..3..0..0..0....1..2..0..1..2..0
..2..0..1..2..0..1....0..0..0..0..0..0....1..2..0..1..2..0....0..2..1..3..2..1
..2..1..0..2..1..0....0..1..2..0..1..2....3..2..1..0..2..1....0..0..3..0..0..3
..0..0..0..0..0..3....1..0..2..1..3..2....0..0..0..0..0..0....1..2..0..1..2..0
..2..0..1..2..3..1....0..0..0..3..0..0....1..2..0..1..2..0....3..2..1..3..2..1
..2..1..0..2..1..0....0..1..2..0..1..2....0..2..1..0..2..1....0..0..3..0..0..3
..0..0..3..0..0..0....1..3..2..1..3..2....0..0..0..0..0..0....1..2..0..1..2..0
..2..3..1..2..0..1....3..0..0..3..0..0....1..2..0..1..2..3....3..2..1..3..2..1

Crossrefs

Row 7 of A252384.

Sequence in context: A090057 A287173 A204753 * A020389 A252609 A185680

Adjacent sequences: A252388 A252389 A252390 * A252392 A252393 A252394

Keyword

nonn

Author

R. H. Hardin, Dec 17 2014

Status

approved