OFFSET
1,1
COMMENTS
Row 2 of A267974.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 70*a(n-1) -2030*a(n-2) +30793*a(n-3) -246680*a(n-4) +794920*a(n-5) +1553979*a(n-6) -13039450*a(n-7) -13949950*a(n-8) +88507965*a(n-9) +242460400*a(n-10) +242460400*a(n-11) +88507965*a(n-12) -13949950*a(n-13) -13039450*a(n-14) +1553979*a(n-15) +794920*a(n-16) -246680*a(n-17) +30793*a(n-18) -2030*a(n-19) +70*a(n-20) -a(n-21)
EXAMPLE
Some solutions for n=4
..0..3..3..2....0..3..3..2....0..2..1..0....1..0..3..1....1..0..2..0
..1..2..0..0....1..0..2..0....3..0..1..3....1..3..1..2....3..2..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 23 2016
STATUS
approved