A222161 Number of (n+3)X1 arrays of occupancy after each element moves up to +-3 places but not 0 and without 2-loops

13, 57, 205, 733, 2627, 9305, 32576, 113448, 394406, 1369551, 4750768, 16468347, 57064823, 197691644, 684764755, 2371639753, 8213463074, 28443621204, 98498816070, 341089856906, 1181139073972, 4090059069992, 14163013655470

Offset

1,1

Comments

Column 3 of A222165

Links

R. H. Hardin, Table of n, a(n) for n = 1..45

Formula

Empirical: a(n) = 7*a(n-1) -13*a(n-2) -3*a(n-3) +21*a(n-4) -41*a(n-6) +83*a(n-7) +30*a(n-8) -216*a(n-9) +17*a(n-10) +214*a(n-11) -19*a(n-12) -101*a(n-13) +5*a(n-14) -9*a(n-15) -5*a(n-16) +45*a(n-17) -12*a(n-18) -21*a(n-19) +2*a(n-20) +a(n-21)

Example

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

Crossrefs

Sequence in context: A210290 A007202 A368813 * A218593 A358303 A212405

Adjacent sequences: A222158 A222159 A222160 * A222162 A222163 A222164

Keyword

nonn

Author

R. H. Hardin Feb 10 2013

Status

approved