A252409 Number of (2+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 2 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 2 3 4 6 or 7

293, 442, 774, 1157, 2489, 5060, 8307, 19629, 41216, 69493, 168252, 355926, 607953, 1485818, 3150880, 5435149, 13364581, 28381270, 49366029, 121983257, 259326130, 454266335, 1127069084, 2398177242, 4225704669, 10519451346, 22399493726

Offset

1,1

Comments

Row 2 of A252407

Links

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

Formula

Empirical: a(n) = 20*a(n-3) -124*a(n-6) +249*a(n-9) -145*a(n-12) -58*a(n-15) +74*a(n-18) -15*a(n-21) for n>26

Example

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

Crossrefs

Sequence in context: A248210 A142284 A245583 * A251682 A251675 A142784

Adjacent sequences: A252406 A252407 A252408 * A252410 A252411 A252412

Keyword

nonn

Author

R. H. Hardin, Dec 17 2014

Status

approved