A280156 Number of nX3 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
2, 8, 31, 94, 305, 950, 2901, 8728, 26068, 77326, 228367, 671446, 1967328, 5745190, 16730555, 48594066, 140815777, 407186706, 1175159395, 3385527188, 9737463217, 27964574958, 80197812317, 229694924100, 657073271390, 1877519404364
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..0..0. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..0..0. .0..0..1 ..0..0..0. .1..1..0. .0..1..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0 ..0..0..1. .1..1..1. .0..1..1. .0..0..1. .0..0..0. .0..0..0. .1..1..0 ..0..0..0. .1..1..1. .0..0..1. .0..1..1. .1..0..0. .0..0..1. .1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A280161.
Formula
Empirical: a(n) = 6*a(n-1) -7*a(n-2) -18*a(n-3) +45*a(n-4) -22*a(n-5) -38*a(n-6) +74*a(n-7) -39*a(n-8) -2*a(n-9) +4*a(n-10) +2*a(n-11) -8*a(n-12) -4*a(n-13) -a(n-14) for n>19
Comments