OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-5) - 2*a(n-6) + 4*a(n-7) - a(n-10).
Empirical g.f.: x*(1 + x^3 - 2*x^4 + 3*x^5 - x^8) / (1 - 2*x - 2*x^5 + 2*x^6 - 4*x^7 + x^10). - Colin Barker, Jan 08 2019
EXAMPLE
Some solutions for n=4:
..1..6..3..4..9....1..6..7..4..9...10..2.12..4.14....5..2..7..4..9
.10..0.12..2.14...10..0.12..2..3....6..0..1..9..3...10..0..1.13..3
.11..5.13..7..8...11..5.13.14..8...11..5.13..7..8...11.12..6.14..8
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2015
STATUS
approved