OFFSET
1,3
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 5*a(n-2) - 6*a(n-3) + 7*a(n-4) - 4*a(n-5) - a(n-6) + 5*a(n-7) - 4*a(n-8) + 2*a(n-9) - a(n-10).
Empirical g.f.: x^2*(1 + 4*x - 8*x^2 + 19*x^3 - 17*x^4 + 13*x^5 - 8*x^6 + 2*x^7 - x^8) / (1 - 2*x - 5*x^2 + 6*x^3 - 7*x^4 + 4*x^5 + x^6 - 5*x^7 + 4*x^8 - 2*x^9 + x^10). - Colin Barker, Jan 07 2019
EXAMPLE
Some solutions for n=4:
..1..6..5..4..7....1..2..3..8..7....5..6..3..8..7....5..2..3..8..7
..0.11.10..3.14....0.11.10.13.12....0..1.10.11..4....0..1.10.13.12
..2.12.13..8..9....5..6..4.14..9....2.12.13.14..9...11..6..4.14..9
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 12 2015
STATUS
approved