OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..50
EXAMPLE
Some solutions for n=3:
..0..x..1..x..2....0..x..1..x..2....0..x..1..x..2....0..x..1..x..2
..x..3..x..4..x....x..3..x..4..x....x..3..x..0..x....x..3..x..4..x
..5..x..2..x..1....5..x..0..x..3....4..x..5..x..3....5..x..6..x..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 24 2012
EXTENSIONS
a(0)=1 prepended and terms a(13) and beyond from Andrew Howroyd, Jun 25 2017
STATUS
approved