A208046 Number of n X 4 0..3 arrays with new values 0..3 introduced in row major order and no element equal to any horizontal, vertical or antidiagonal neighbor (colorings ignoring permutations of colors).
5, 32, 244, 1904, 14976, 118096, 931968, 7356288, 58068800, 458389760, 3618506752, 28564366592, 225486229504, 1779981604864, 14051122574336, 110919150841856, 875592537571328, 6911901929525248, 54562352063938560, 430713614487224320
Offset: 1
Keywords
Examples
Some solutions for n=4: 0 1 2 1 0 1 2 0 0 1 0 1 0 1 2 3 0 1 2 3 2 3 0 2 2 0 1 2 2 3 2 3 2 3 0 1 2 3 0 1 1 2 1 3 1 3 0 1 0 1 0 1 0 1 3 0 1 2 3 2 3 0 2 0 2 1 2 3 2 3 2 0 2 0 2 1 3 1 0 1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A208050.
Formula
Empirical: a(n) = 12*a(n-1) - 40*a(n-2) + 68*a(n-3) - 64*a(n-4) for n>5.
Empirical g.f.: x*(5 - 28*x + 60*x^2 - 84*x^3 + 32*x^4) / (1 - 12*x + 40*x^2 - 68*x^3 + 64*x^4). - Colin Barker, Mar 06 2018
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