A208706 Number of n X 5 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
16, 356, 8128, 185344, 4226368, 96373248, 2197585152, 50111214592, 1142678737920, 26056337063936, 594158864306176, 13548518165364736, 308944889161203712, 7044825373067575296, 160642128347753938944
Offset: 1
Keywords
Examples
Some solutions for n=4: ..0..0..1..0..0....0..0..1..0..0....0..0..1..1..1....0..1..1..0..1 ..1..1..0..1..0....1..1..1..1..0....0..1..0..0..0....1..0..1..0..0 ..1..0..1..1..0....1..0..1..1..0....0..0..1..0..0....1..0..1..1..1 ..0..1..0..1..0....1..1..0..0..1....1..1..1..0..1....0..0..1..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A208709.
Formula
Empirical: a(n) = 24*a(n-1) - 28*a(n-2) + 16*a(n-3) for n>4.
Empirical g.f.: 4*x*(4 - 7*x + 8*x^2 - 4*x^3) / (1 - 24*x + 28*x^2 - 16*x^3). - Colin Barker, Jul 06 2018
Comments