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

1,1

Links

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

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

Example

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

Crossrefs

Column 2 of A250229.

Sequence in context: A147157 A146826 A059400 * A250271 A289842 A077776

Adjacent sequences: A250220 A250221 A250222 * A250224 A250225 A250226

Keyword

nonn

Author

R. H. Hardin, Nov 14 2014

Status

approved