A232296 Number of 2Xn 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally.
1, 15, 97, 587, 3615, 22387, 138505, 856719, 5299373, 32780447, 202770557, 1254280765, 7758622663, 47992624925, 296868677731, 1836344895365, 11359105312193, 70264182844421, 434634177177689, 2688522947592119
Offset: 1
Keywords
Examples
Some solutions for n=7 ..1..2..1..1..1..2..0....1..2..2..1..1..2..1....1..2..2..2..1..1..2 ..2..0..2..0..2..1..0....0..1..0..1..2..0..2....0..1..2..1..2..2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 6*a(n-1) -a(n-2) +13*a(n-3) +2*a(n-4) -a(n-5) +a(n-6) -14*a(n-7) -2*a(n-8) +5*a(n-9).
Empirical: G.f.: -x*(1+9*x+8*x^2+7*x^3-7*x^4-6*x^5-13*x^6+3*x^7+5*x^8) / ( (5*x^6 +8*x^5 -3*x^4 -8*x^3 -6*x^2 -5*x+1)*(x^3 -2*x^2 +x-1) ). - R. J. Mathar, Nov 27 2013
Comments