A231646 Number of nX3 0..2 arrays with no element less than a strict majority of its horizontal and vertical neighbors

9, 104, 920, 7682, 61574, 490760, 3929027, 31501117, 252454167, 2022844426, 16209670759, 129896538285, 1040912909763, 8341204621591, 66841228911422, 535624801555647, 4292168448581044, 34394795269925139, 275618732897288063

Offset

1,1

Comments

Column 3 of A231651

Links

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

Formula

Empirical: a(n) = 18*a(n-1) -133*a(n-2) +640*a(n-3) -2309*a(n-4) +5762*a(n-5) -9918*a(n-6) +8864*a(n-7) +2970*a(n-8) -18151*a(n-9) +23183*a(n-10) +21799*a(n-11) -75109*a(n-12) +56329*a(n-13) -9892*a(n-14) -115814*a(n-15) +105665*a(n-16) +64162*a(n-17) -38348*a(n-18) +8767*a(n-19) +54790*a(n-20) -95246*a(n-21) -139155*a(n-22) +81259*a(n-23) +104482*a(n-24) +18968*a(n-25) -2909*a(n-26) -41630*a(n-27) -37578*a(n-28) +6670*a(n-29) +17693*a(n-30) +5629*a(n-31) -713*a(n-32) -928*a(n-33) -300*a(n-34) -52*a(n-35) -4*a(n-36) for n>37

Example

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

Crossrefs

Sequence in context: A356244 A367447 A081461 * A110698 A012485 A052503

Adjacent sequences: A231643 A231644 A231645 * A231647 A231648 A231649

Keyword

nonn

Author

R. H. Hardin, Nov 12 2013

Status

approved