A230826 Number of nX3 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally 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, no adjacent elements equal, and upper left element zero

0, 2, 8, 10, 38, 130, 456, 1610, 5740, 20556, 73752, 264880, 951934, 3422488, 12308046, 44269818, 159246922, 572876878, 2060948396, 7414494752, 26674762316, 95966982642, 345258365956, 1242130065600, 4468792097374, 16077307478686

Offset

1,2

Comments

Column 3 of A230831

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -37*a(n-2) +59*a(n-3) -25*a(n-4) -31*a(n-5) +33*a(n-6) -22*a(n-7) -4*a(n-8) +46*a(n-9) -2*a(n-10) -18*a(n-11) -4*a(n-12) for n>17

Example

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

Crossrefs

Sequence in context: A066707 A107227 A188539 * A071184 A174153 A171976

Adjacent sequences: A230823 A230824 A230825 * A230827 A230828 A230829

Keyword

nonn

Author

R. H. Hardin, Oct 30 2013

Status

approved