A251830 Number of (n+2) X (1+2) 0..3 arrays with no row, column, diagonal or antidiagonal in any 3 X 3 subblock summing to 3 4 5 or 6.

678, 3354, 18124, 97316, 518514, 2764828, 14778068, 79010324, 422170156, 2255865816, 12055912400, 64428206472, 344303766674, 1839970274068, 9832898770152, 52547443489104, 280815669383888, 1500690900097558

Offset

1,1

Comments

Column 1 of A251836.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +8*a(n-2) +41*a(n-3) +68*a(n-4) +33*a(n-5) -207*a(n-6) -543*a(n-7) -471*a(n-8) -30*a(n-9) +202*a(n-10) -352*a(n-11) -548*a(n-12) +37*a(n-13) +640*a(n-14) +670*a(n-15) +347*a(n-16) +235*a(n-17) -124*a(n-18) -97*a(n-19) -106*a(n-20) -51*a(n-21) -56*a(n-22) +8*a(n-23) +4*a(n-24) +8*a(n-25) +4*a(n-27) for n > 29.

Example

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

Crossrefs

Cf. A251836.

Sequence in context: A031524 A158385 A251836 * A250872 A186127 A097771

Adjacent sequences: A251827 A251828 A251829 * A251831 A251832 A251833

Keyword

nonn

Author

R. H. Hardin, Dec 09 2014

Status

approved