A188559 Number of 8 X n binary arrays without the pattern 0 1 diagonally, vertically, antidiagonally or horizontally.
9, 17, 32, 60, 112, 208, 384, 704, 1280, 2304, 4097, 7181, 12381, 20965, 34831, 56751, 90683, 142163, 218790, 330818, 491870, 719790, 1037650, 1474930, 2068890, 2866154, 3924527, 5315067, 7124435, 9457547, 12440553, 16224169, 20987389
Offset: 1
Keywords
Examples
Some solutions for 8 X 3: ..1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1 ..1..1..1....1..1..0....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1 ..1..1..1....1..0..0....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1 ..1..1..1....0..0..0....1..1..1....1..1..1....1..1..1....1..1..0....1..1..1 ..1..1..1....0..0..0....1..1..1....1..1..1....1..1..1....1..0..0....1..1..0 ..1..1..0....0..0..0....1..1..1....1..0..0....1..1..1....0..0..0....1..0..0 ..0..0..0....0..0..0....1..1..1....0..0..0....1..1..0....0..0..0....0..0..0 ..0..0..0....0..0..0....1..0..0....0..0..0....0..0..0....0..0..0....0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Crossrefs
Cf. A188553.
Formula
Empirical: a(n) = (1/40320)*n^8 - (1/2016)*n^7 + (19/2880)*n^6 - (7/180)*n^5 + (1247/5760)*n^4 - (85/288)*n^3 + (17911/10080)*n^2 + (1961/840)*n + 5.
Conjectures from Colin Barker, Apr 28 2018: (Start)
G.f.: x*(9 - 64*x + 203*x^2 - 372*x^3 + 430*x^4 - 320*x^5 + 150*x^6 - 40*x^7 + 5*x^8) / (1 - x)^9.
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.
(End)
Comments