A221323 - OEIS

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A221323

Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.

7, 119, 2008, 33873, 571358, 9637322, 162555929, 2741882383, 46248186229, 780082534460, 13157894317753, 221938287447408, 3743501973486176, 63142809559541159, 1065049364666447387, 17964518161956501475

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OFFSET

1,1

COMMENTS

Column 3 of A221328.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..69

FORMULA

Empirical: a(n) = 23*a(n-1) - 110*a(n-2) + 111*a(n-3) - 6*a(n-4) - 8*a(n-5).

Empirical g.f.: x*(1 - x)*(7 - 35*x + 6*x^2 + 8*x^3) / (1 - 23*x + 110*x^2 - 111*x^3 + 6*x^4 + 8*x^5). - Colin Barker, Aug 05 2018

EXAMPLE

Some solutions for n=3: