A230894 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, no adjacent elements equal, and upper left element zero.

0, 2, 14, 34, 198, 810, 3706, 16918, 76318, 347442, 1575090, 7148582, 32438126, 147179442, 667843250, 3030291798, 13749921166, 62390019330, 283093420626, 1284531566502, 5828537726158, 26446883611922, 120002248379506

Offset

1,2

Comments

Column 3 of A230899

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +3*a(n-2) -25*a(n-3) -8*a(n-4) +82*a(n-5) -8*a(n-6) -132*a(n-7) +80*a(n-8) +12*a(n-9) -32*a(n-10) +16*a(n-11)

Example

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

Crossrefs

Sequence in context: A096311 A034842 A324043 * A291152 A145910 A128126

Adjacent sequences: A230891 A230892 A230893 * A230895 A230896 A230897

Keyword

nonn

Author

R. H. Hardin, Oct 31 2013

Status

approved