A230690 Number of (n+2)X(1+2) 0..2 arrays x(i,j) with each element horizontally, vertically, diagonally or antidiagonally next to at least two elements with value (x(i,j)+1) mod 3, and upper left element zero

2, 4, 21, 139, 913, 6276, 43544, 301609, 2092432, 14518601, 100730876, 698916053, 4849388894, 33647114207, 233458408129, 1619836235637, 11239129382534, 77981980905001, 541072982103756, 3754200244270001, 26048278095561922

Offset

1,1

Comments

Column 1 of A230694

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -2*a(n-2) +26*a(n-3) -115*a(n-4) +96*a(n-5) -242*a(n-6) +559*a(n-7) -460*a(n-8) +731*a(n-9) -1062*a(n-10) +238*a(n-11) -1160*a(n-12) +1284*a(n-13) +261*a(n-14) +936*a(n-15) -830*a(n-16) +1008*a(n-17) -453*a(n-19) +128*a(n-20) -5*a(n-21) -a(n-22)

Example

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

Crossrefs

Sequence in context: A233289 A296282 A308763 * A219745 A151803 A151804

Adjacent sequences: A230687 A230688 A230689 * A230691 A230692 A230693

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved