A202198 Number of (n+2) X 6 binary arrays avoiding patterns 001 and 101 in rows and columns.
756, 2688, 7560, 18144, 38808, 76032, 138996, 240240, 396396, 628992, 965328, 1439424, 2093040, 2976768, 4151196, 5688144, 7671972, 10200960, 13388760, 17365920, 22281480, 28304640, 35626500, 44461872, 55051164, 67662336, 82592928
Offset: 1
Keywords
Examples
Some solutions for n=3: ..0..1..1..1..1..1....1..1..1..0..0..0....0..1..1..0..0..0....1..1..1..1..1..1 ..1..1..1..1..1..1....1..1..1..0..0..0....0..1..1..0..0..0....1..1..1..1..1..1 ..0..1..1..1..0..0....1..1..0..0..0..0....0..1..1..0..0..0....1..1..1..1..1..1 ..0..1..1..0..0..0....1..1..0..0..0..0....0..1..1..0..0..0....1..1..1..0..0..0 ..0..1..1..0..0..0....1..1..0..0..0..0....0..1..1..0..0..0....0..1..1..0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A202202.
Formula
Empirical: a(n) = (n+6)*(n+5)*(n+4)*(n+3)*(n+2)^2/10.
Conjectures from Colin Barker, May 27 2018: (Start)
G.f.: 12*x*(63 - 217*x + 385*x^2 - 399*x^3 + 245*x^4 - 83*x^5 + 12*x^6) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.
(End)
Comments