OFFSET
1,1
COMMENTS
Row 7 of A258730.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/5040)*n^7 + (11/720)*n^6 + (361/720)*n^5 + (1285/144)*n^4 + (40822/45)*n^3 + (1121411/180)*n^2 + (480457/35)*n + 7848 for n>5.
Empirical g.f.: x*(65536 - 361268*x + 751702*x^2 - 591152*x^3 - 236266*x^4 + 807960*x^5 - 664864*x^6 + 371040*x^7 - 206700*x^8 + 10940*x^9 + 117664*x^10 - 82072*x^11 + 17481*x^12) / (1 - x)^8. - Colin Barker, Jan 26 2018
EXAMPLE
Some solutions for n=2:
..0....0....1....0....1....1....0....0....1....0....1....0....1....1....1....2
..3....1....0....1....0....2....0....1....0....3....0....2....1....2....3....0
..3....0....1....2....0....1....2....1....2....1....2....0....2....0....1....0
..1....0....1....1....1....3....3....0....1....3....0....3....2....3....1....3
..1....0....3....2....0....0....0....3....3....1....0....2....0....3....0....1
..1....1....3....0....3....1....0....3....2....1....0....3....0....3....0....3
..3....1....1....0....3....2....2....2....3....1....2....0....0....3....3....1
..3....2....1....0....0....0....2....3....3....1....3....3....1....1....0....2
..1....0....2....0....3....3....1....3....3....3....3....3....1....3....1....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 08 2015
STATUS
approved