OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 20*a(n-1) - 145*a(n-2) + 425*a(n-3) - 252*a(n-4) - 605*a(n-5) - 53*a(n-6) + 15*a(n-7).
Empirical g.f.: 2*x*(3 - 42*x + 183*x^2 - 182*x^3 - 286*x^4 - 22*x^5 + 7*x^6) / ((1 - 5*x)*(1 - 15*x + 70*x^2 - 75*x^3 - 123*x^4 - 10*x^5 + 3*x^6)). - Colin Barker, Jan 23 2019
EXAMPLE
Some solutions for n=6:
..0. .3. .5. .4. .2. .5. .4. .1. .0. .5. .5. .0. .2. .0. .0. .3
..1. .0. .5. .3. .0. .4. .5. .5. .2. .0. .0. .3. .4. .0. .0. .1
..0. .4. .2. .1. .0. .2. .1. .1. .1. .5. .3. .5. .5. .5. .5. .3
..5. .4. .5. .5. .3. .0. .3. .4. .2. .2. .1. .5. .2. .5. .3. .1
..5. .0. .2. .3. .1. .5. .1. .5. .0. .3. .2. .2. .5. .3. .0. .4
..2. .4. .2. .4. .0. .4. .0. .0. .1. .1. .0. .3. .2. .5. .2. .2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 28 2016
STATUS
approved