A229691 Number of defective 3-colorings of an nX5 0..2 array connected horizontally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.
12, 1171, 35825, 848937, 17724789, 342532665, 6279934941, 110801828529, 1898544262293, 31786996628745, 522316663574733, 8450380115641377, 134940473888031045, 2130891564532483449, 33326706458497564413
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..1..0..1..0....0..1..2..1..0....0..1..0..1..2....0..1..2..0..1 ..0..1..0..1..2....2..1..0..1..2....2..1..2..0..2....0..2..1..0..2 ..0..0..2..1..2....2..1..1..0..2....0..2..1..1..0....1..2..1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 45*a(n-1) -729*a(n-2) +4995*a(n-3) -13122*a(n-4) +14580*a(n-5) -5832*a(n-6) for n>7.
Empirical: 12*x -x^2*(-1171+16870*x-90471*x^2+210096*x^3-212220*x^4+81648*x^5) / (18*x^2-15*x+1)^3. - R. J. Mathar, Sep 29 2013
Comments