A240637 - OEIS

A240637

Number of n X 2 0..3 arrays with no element equal to one or three horizontal or vertical neighbors, with new values 0..3 introduced in row major order.

1, 5, 27, 193, 1391, 10072, 72941, 528283, 3826157, 27711478, 200704271, 1453628917, 10528111931, 76251331828, 552260998337, 3999827976463, 28969316843801, 209814352850962, 1519609968699971, 11005988987858473

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OFFSET

1,2

COMMENTS

Column 2 of A240642.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 6*a(n-1) + 10*a(n-2) - 6*a(n-3) - 9*a(n-4) for n>6.

Empirical g.f.: x*(1 - x - 13*x^2 - 13*x^3 + 2*x^4 + 3*x^5) / ((1 - x)*(1 + x)*(1 - 6*x - 9*x^2)). - Colin Barker, Mar 19 2018

EXAMPLE

Some solutions for n=4: