A228688 Number of 7Xn binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally.
128, 577, 21305, 176032, 4008817, 44171841, 806190208, 10258304689, 168184756793, 2301665823616, 35784406285057, 508094306671233, 7692715116119040, 111277331056067617, 1662525457133097145
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..0..0..1....0..1..0..0....0..1..0..0....0..0..0..0....0..0..0..0 ..0..0..0..0....0..0..0..0....0..1..0..1....1..0..0..0....1..0..0..0 ..0..0..1..0....0..1..0..0....0..0..0..0....1..0..0..0....1..0..0..0 ..1..0..0..0....0..1..0..1....0..0..0..0....0..0..0..0....1..0..1..0 ..0..0..0..1....0..0..0..0....0..1..0..1....0..0..0..0....1..0..0..0 ..0..1..0..0....0..0..1..0....0..0..0..0....1..0..1..0....1..0..0..0 ..0..1..0..0....1..0..1..0....0..0..1..0....0..0..1..0....0..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 9*a(n-1) +184*a(n-2) -1201*a(n-3) -7155*a(n-4) +46048*a(n-5) +70745*a(n-6) -591673*a(n-7) -154744*a(n-8) +3207657*a(n-9) -715173*a(n-10) -7580648*a(n-11) +3369552*a(n-12) +7114920*a(n-13) -3800952*a(n-14) -1923264*a(n-15) +1083456*a(n-16)
Comments