OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) + 18*a(n-3) + 120*a(n-5) - 24*a(n-6) + 288*a(n-7) + 256*a(n-10) for n>11.
Empirical g.f.: x^2*(19 - 17*x + 46*x^2 - 16*x^3 + 64*x^4 - 8*x^5 - 104*x^6 + 256*x^7 - 256*x^8 + 768*x^9) / (1 - 3*x - 18*x^3 - 120*x^5 + 24*x^6 - 288*x^7 - 256*x^10). - Colin Barker, Jan 08 2019
EXAMPLE
Some solutions for n=4:
.12..6.14..2..9....5.13..1..8..3...12..0.14..2..3...12..6..1..2..3
..0..1.19..3..4....0.11..2..7..4...10..1..6.13..4....0.11.19..7..4
..5.10..7..8.13...22..6.24.12..9....5.23..7..8..9....5.16.24..8..9
.20.11.22.17.24...10.21.16.23.14...20.11.22.17.24...10.21.22.13.14
.15.16.21.18.23...15.20.17.18.19...15.16.21.18.19...15.20.17.18.23
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 17 2015
STATUS
approved