A202658 Number of -2..2 arrays of n elements with first through fourth differences also in -2..2.

5, 19, 57, 127, 213, 363, 613, 1055, 1815, 3159, 5503, 9609, 16773, 29281, 51125, 89277, 155899, 272315, 475793, 831415, 1452927, 2539213, 4437877, 7756367, 13556573, 23694815, 41415935, 72391801, 126536987, 221182305, 386622379

Offset: 1

Author

R. H. Hardin Dec 22 2011

Keywords

• nonn

Comments

Column 2 of A202664

Examples

			Some solutions for n=10
.-2...-2....1...-2....0....0...-1....0....0....1...-2....1....0....1...-2....2
..0...-1....2....0...-1....1....1....2....0...-1....0....0...-2....2....0....2
..0....0....2....0....0....0....1....2...-1...-2....1...-1...-2....2....0....1
..0....1....2...-1....1...-1....0....1...-1...-2....2...-1...-2....2...-1....0
..0....1....2...-1....2...-2...-1....0....0...-2....2...-1...-2....2...-2....0
..0....1....2....0....2...-2...-1....0....1...-2....2...-1...-1....1...-2....1
..1....1....1....1....2...-1...-1....0....2...-2....1...-1....1....0...-1....2
..2....0...-1....1....2....0...-1....0....2...-1....0....0....2....0....0....2
..2...-1...-2....1....1....0....0....0....1....0...-1....1....2....0....1....1
..1...-2...-2....0...-1....0....1....1....0....1...-1....0....2...-1....1....0
		

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +2*a(n-4) -a(n-5) -2*a(n-7) -a(n-8) -4*a(n-10) -7*a(n-11) -10*a(n-12) -7*a(n-13) -6*a(n-14) -a(n-15) +6*a(n-16) +9*a(n-17) +8*a(n-18) +6*a(n-19) +4*a(n-20) +2*a(n-21) for n>27