A250223 Number of length n+1 0..2 arrays with the sum of the cubes of adjacent differences multiplied by some arrangement of +-1 equal to zero.

3, 11, 27, 79, 223, 651, 1907, 5639, 16967, 52131, 163291, 518687, 1659887, 5320123, 17004227, 54054071, 170674327, 535082323, 1666053035, 5154907599, 15861068351, 48568847467, 148122439315, 450214152039, 1364634624743, 4127055619331

Offset: 1

Author

R. H. Hardin, Nov 14 2014

Keywords

• nonn

Examples

			Some solutions for n=6:
..1....1....2....2....0....0....2....2....2....2....0....0....0....2....1....2
..0....0....2....2....2....0....0....2....0....0....0....2....0....1....0....1
..2....2....1....0....1....2....2....1....0....2....1....1....0....1....2....0
..0....1....2....1....1....0....1....1....2....2....1....2....2....0....0....2
..0....0....0....1....0....0....0....2....2....2....1....0....0....1....1....0
..1....2....0....0....2....2....2....1....0....1....0....1....1....1....1....1
..1....1....2....2....2....0....0....0....2....2....0....2....0....2....1....2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..104

Crossrefs

Column 2 of A250229.

Formula

Empirical: a(n) = 15*a(n-1) - 98*a(n-2) + 366*a(n-3) - 861*a(n-4) + 1323*a(n-5) - 1328*a(n-6) + 840*a(n-7) - 304*a(n-8) + 48*a(n-9) for n>12.

Empirical g.f.: x*(3 - 34*x + 156*x^2 - 346*x^3 + 241*x^4 + 668*x^5 - 2240*x^6 + 3600*x^7 - 3984*x^8 + 3200*x^9 - 1664*x^10 + 384*x^11) / ((1 - x)^4*(1 - 2*x)^4*(1 - 3*x)). - Colin Barker, Nov 12 2018