A230801 Number of nX3 0..3 arrays x(i,j) with each element horizontally or vertically next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, and upper left element zero

0, 2, 14, 40, 298, 1546, 8704, 50450, 286426, 1650968, 9481842, 54537066, 313793424, 1805343618, 10388621898, 59779183384, 343996534162, 1979528849242, 11391230879008, 65551238025090, 377217128316090, 2170711959147608

Offset

1,2

Comments

Column 3 of A230805

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -7*a(n-2) -40*a(n-3) +3*a(n-4) +221*a(n-5) -237*a(n-6) -55*a(n-7) +182*a(n-8) -270*a(n-9) +324*a(n-10) -172*a(n-11) +112*a(n-12) -64*a(n-13)

Example

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

Crossrefs

Sequence in context: A329735 A290124 A192349 * A231081 A364218 A152670

Adjacent sequences: A230798 A230799 A230800 * A230802 A230803 A230804

Keyword

nonn

Author

R. H. Hardin, Oct 30 2013

Status

approved