A251890 Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum not 2 3 6 or 7 and every diagonal and antidiagonal sum 2 3 6 or 7.

1280, 530, 778, 1316, 1958, 2660, 4490, 7250, 10634, 17954, 28994, 42530, 71810, 115970, 170114, 287234, 463874, 680450, 1148930, 1855490, 2721794, 4595714, 7421954, 10887170, 18382850, 29687810, 43548674, 73531394, 118751234

Offset

1,1

Comments

Column 4 of A251894.

Links

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

Formula

Empirical: a(n) = a(n-1) + 4*a(n-3) - 4*a(n-4) for n>9.

Empirical g.f.: 2*x*(640 - 375*x + 124*x^2 - 2291*x^3 + 1821*x^4 - 145*x^5 - 161*x^6 + 96*x^7 + 288*x^8) / ((1 - x)*(1 - 4*x^3)). - Colin Barker, Mar 20 2018

Example

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

Crossrefs

Cf. A251894.

Sequence in context: A251097 A031798 A293923 * A251889 A251886 A234137

Adjacent sequences: A251887 A251888 A251889 * A251891 A251892 A251893

Keyword

nonn

Author

R. H. Hardin, Dec 10 2014

Status

approved