A252451 Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 4 6 or 7

228, 334, 959, 2643, 7223, 20242, 56643, 157904, 441732, 1236191, 3457251, 9675077, 27082988, 75811167, 212260118, 594414790, 1664804901, 4663453223, 13065449675, 36610452250, 102601066175, 287584652400, 806202954272, 2260411478111

Offset

1,1

Comments

Column 2 of A252457

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -2*a(n-2) +7*a(n-3) -29*a(n-4) -11*a(n-5) -10*a(n-6) +60*a(n-7) +72*a(n-8) +39*a(n-9) -48*a(n-10) -69*a(n-11) -75*a(n-12) -36*a(n-13) -9*a(n-14) +30*a(n-15) +49*a(n-16) +44*a(n-17) +14*a(n-18) -7*a(n-19) -13*a(n-20) -7*a(n-21) -2*a(n-22) for n>25

Example

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

Crossrefs

Sequence in context: A343169 A190027 A090943 * A305063 A258550 A335269

Adjacent sequences: A252448 A252449 A252450 * A252452 A252453 A252454

Keyword

nonn

Author

R. H. Hardin, Dec 17 2014

Status

approved