A217959 Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..2 n X 3 array.
9, 91, 835, 7765, 72257, 672627, 6261827, 58295677, 542717361, 5052561371, 47038082435, 437912812805, 4076859114817, 37954542163107, 353347327405987, 3289575547592237, 30625128435267441, 285112312553286091
Offset: 1
Keywords
Examples
Some solutions for n=3: ..1..0..1....2..1..1....1..0..0....0..0..1....2..0..1....2..0..0....0..0..0 ..0..0..2....1..0..0....1..0..0....1..1..2....0..0..2....2..0..0....1..0..1 ..1..1..2....1..0..0....1..0..2....1..1..2....0..0..0....1..0..2....1..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..181
Crossrefs
Cf. A217964.
Formula
Empirical: a(n) = 10*a(n-1) - 4*a(n-2) - 20*a(n-3) - 23*a(n-4) - 10*a(n-5).
Empirical g.f.: x*(9 + x - 39*x^2 - 41*x^3 - 26*x^4) / (1 - 10*x + 4*x^2 + 20*x^3 + 23*x^4 + 10*x^5). - Colin Barker, Jul 23 2018
Comments