A252560 Number of (2+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 1, 2, 4, 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 1, 2, 4, 6 or 7.

747, 889, 1752, 3178, 8508, 21797, 42359, 123304, 335953, 649461, 1947522, 5522343, 10600641, 32456683, 94716620, 180887838, 562002424, 1672252134, 3182740701, 9984306730, 30080613817, 57127667585, 180301146839, 547401415073

Offset

1,1

Comments

Row 2 of A252558.

Links

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

Formula

Empirical: a(n) = 42*a(n-3) -595*a(n-6) +3251*a(n-9) -5703*a(n-12) +8191*a(n-15) -8486*a(n-18) +5741*a(n-21) -3340*a(n-24) +900*a(n-27) for n > 32.

Example

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

Crossrefs

Cf. A252558.

Sequence in context: A051978 A235732 A235513 * A252453 A252946 A242150

Adjacent sequences: A252557 A252558 A252559 * A252561 A252562 A252563

Keyword

nonn

Author

R. H. Hardin, Dec 18 2014

Status

approved