A201040 Number of -6..6 arrays of n elements with adjacent element differences also in -6..6.

13, 127, 1287, 13021, 131781, 1333683, 13497523, 136601483, 1382473365, 13991301963, 141598771951, 1433048351749, 14503145402825, 146778876175813, 1485473522677393, 15033713597401013, 152148484020986879

Offset: 1

Author

R. H. Hardin, Nov 26 2011

Keywords

• nonn

Comments

Column 6 of A201042.

Examples

			Some solutions for n=4:
..6....3...-1...-3....3...-3....0...-6...-4...-1...-4...-2....2...-1...-5...-3
..1...-2....2....2....2...-5...-2....0...-1...-2...-2....1...-2....2...-2...-1
.-3....0....0...-4...-4....1....2...-5...-6...-5....0....1...-4....2....0...-3
.-6....0....2...-5...-3...-3....3...-1...-3...-4...-3...-1...-1...-3....0...-4
		

Links

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

Crossrefs

Cf. A201042.

Formula

Empirical: a(n) = 10*a(n-1) +3*a(n-2) -18*a(n-3) -a(n-4) +8*a(n-5) -a(n-7).

Empirical g.f.: x*(13 - 3*x - 22*x^2 + 4*x^3 + 9*x^4 - x^5 - x^6) / ((1 - x)*(1 - 9*x - 12*x^2 + 6*x^3 + 7*x^4 - x^5 - x^6)). - Colin Barker, May 21 2018