A258960 Number of (n+2) X (2+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.

158, 344, 274, 467, 614, 951, 1228, 1951, 2652, 4261, 5688, 9170, 12562, 20311, 27308, 44158, 60442, 97842, 131938, 213491, 291732, 472335, 638108, 1032723, 1409172, 2281540, 3086358, 4995377, 6808672, 11023318, 14926538, 24160156, 32902102

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-2) - a(n-3) + 4*a(n-4) - 4*a(n-5) - 3*a(n-6) + 3*a(n-7) for n>13.

Empirical g.f.: x*(158 + 186*x - 228*x^2 + 7*x^3 - 415*x^4 - 600*x^5 + 884*x^6 + 172*x^7 - 374*x^8 + 117*x^9 + 59*x^10 - 8*x^11 - 8*x^12) / ((1 - x)*(1 - x^2 - 4*x^4 + 3*x^6)). - Colin Barker, Dec 23 2018

Example

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

Crossrefs

Column 2 of A258966.

Sequence in context: A352349 A255351 A088728 * A072555 A056088 A189813

Adjacent sequences: A258957 A258958 A258959 * A258961 A258962 A258963

Keyword

nonn

Author

R. H. Hardin, Jun 15 2015

Status

approved