A200457 Number of -n..n arrays x(0..4) of 5 elements with zero sum and nonzero first and second differences.

6, 144, 728, 2334, 5720, 12002, 22276, 38174, 61290, 93704, 137374, 194964, 268842, 362092, 477620, 618954, 789324, 992970, 1233412, 1515270, 1842742, 2220844, 2654034, 3148080, 3707758, 4339192, 5047836, 5840186, 6721964, 7700510, 8781768

Offset: 1

Author

R. H. Hardin Nov 18 2011

Keywords

• nonn

Comments

Row 3 of A200454

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = -a(n-1) +a(n-3) +2*a(n-4) +2*a(n-5) +a(n-6) -a(n-8) -a(n-9) -a(n-10) -2*a(n-11) -2*a(n-12) -2*a(n-13) -a(n-14) +a(n-15) +2*a(n-16) +2*a(n-17) +2*a(n-18) +a(n-19) +a(n-20) +a(n-21) -a(n-23) -2*a(n-24) -2*a(n-25) -a(n-26) +a(n-28) +a(n-29)