OFFSET
1,1
COMMENTS
Column 3 of A227333.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/1307674368000)*n^15 + (1/87178291200)*n^14 + (19/7472424960)*n^13 - (1/191600640)*n^12 + (36577/14370048000)*n^11 - (2689/87091200)*n^10 + (436297/365783040)*n^9 - (2115367/121927680)*n^8 + (6669593/23328000)*n^7 - (13770361/4354560)*n^6 + (104682953/3592512)*n^5 - (2364431063/11975040)*n^4 + (366060925289/378378000)*n^3 - (487180400717/151351200)*n^2 + (2320943983/360360)*n - 5585 for n>6.
EXAMPLE
Some solutions for n=4
..0..0..0....0..0..0....1..0..0....0..0..0....0..0..1....0..0..0....0..0..1
..1..1..1....1..0..0....1..0..0....0..0..1....0..0..1....0..0..0....1..0..1
..1..1..1....0..0..1....0..1..0....0..0..0....0..0..1....0..0..1....0..1..1
..1..0..0....0..1..0....1..0..0....0..1..0....1..1..0....1..1..0....1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jul 07 2013
STATUS
approved