A217881 Number of n element 0..2 arrays with each element the minimum of 6 adjacent elements of a random 0..2 array of n+5 elements.

3, 9, 22, 46, 86, 148, 239, 372, 576, 915, 1520, 2639, 4711, 8471, 15107, 26516, 45758, 77899, 131586, 221935, 375670, 640002, 1097628, 1891754, 3267763, 5643077, 9725666, 16717471, 28666522, 49078549, 83978278, 143744065, 246264367

Offset

1,1

Comments

Column 6 of A217883.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + 3*a(n-7) - a(n-8) + a(n-9) + a(n-10) + a(n-11) + a(n-12) + a(n-13).

Empirical g.f.: x*(1 + x^2)*(1 + x^3 + x^4)*(3 + x^2 + x^3 + x^4 + x^5 + x^6) / (1 - 3*x + 3*x^2 - x^3 - 3*x^7 + x^8 - x^9 - x^10 - x^11 - x^12 - x^13). - Colin Barker, Jul 23 2018

Example

Some solutions for n=4:
..0....0....0....1....0....1....0....2....2....0....0....0....1....0....1....2
..2....0....1....1....2....1....0....2....0....0....1....0....2....2....2....2
..1....1....2....2....1....2....0....1....0....2....1....1....0....0....2....2
..1....2....1....2....0....0....0....0....0....0....0....1....0....0....1....2

Crossrefs

Cf. A217883.

Sequence in context: A064808 A223718 A217882 * A217880 A217879 A217878

Adjacent sequences: A217878 A217879 A217880 * A217882 A217883 A217884

Keyword

nonn

Author

R. H. Hardin, Oct 14 2012

Status

approved