A222551 Number of (n+4)X1 arrays of occupancy after each element moves up to +-4 places but not 0.

121, 427, 1562, 5761, 21239, 78245, 287858, 1059674, 3901868, 14366833, 52894813, 194725954, 716822517, 2638639647, 9712504051, 35749337667, 131581046318, 484294944395, 1782459967105, 6560310404375, 24144873322163, 88863279809958

Offset: 1

Author

R. H. Hardin Feb 24 2013

Keywords

• nonn

Comments

Column 4 of A222555

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..117

Formula

Empirical: a(n) = 9*a(n-1) -28*a(n-2) +35*a(n-3) -15*a(n-4) +12*a(n-5) -96*a(n-6) +274*a(n-7) -265*a(n-8) +24*a(n-9) -7*a(n-10) +29*a(n-11) +3*a(n-12) -a(n-13)