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A279128

Number of n X 2 0..1 arrays with no element equal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

1, 0, 9, 34, 87, 194, 400, 790, 1511, 2830, 5213, 9484, 17080, 30508, 54117, 95434, 167443, 292486, 508912, 882402, 1525219, 2628886, 4519577, 7751888, 13267384, 22662360, 38639553, 65769394, 111771663, 189671306, 321421456, 543987118

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OFFSET

1,3

COMMENTS

Column 2 of A279134.

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) - 7*a(n-2) - 2*a(n-3) + 10*a(n-4) - 2*a(n-5) - 5*a(n-6) + a(n-7) + a(n-8) for n>9.

Empirical g.f.: x*(1 - 5*x + 16*x^2 - 9*x^3 - 30*x^4 + 17*x^5 + 22*x^6 - x^7 - 9*x^8) / ((1 - x)^2*(1 - x - x^2)^3). - Colin Barker, Feb 26 2018

EXAMPLE

Some solutions for n=4: