A219150 - OEIS

A219150

Unchanging value maps: number of n X 2 binary arrays indicating the locations of corresponding elements unequal to no horizontal, antidiagonal or vertical neighbor in a random 0..1 n X 2 array.

2, 4, 9, 21, 49, 115, 269, 628, 1468, 3433, 8025, 18758, 43851, 102512, 239638, 560193, 1309554, 3061318, 7156366, 16729268, 39107635, 91421020, 213712795, 499591476, 1167883505, 2730134349, 6382172117, 14919456700, 34876870155, 81530855583

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OFFSET

1,1

COMMENTS

Column 2 of A219156.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - a(n-2) + 4*a(n-3) + a(n-5).

Empirical g.f.: x*(2 + 3*x^2 - x^3) / (1 - 2*x + x^2 - 4*x^3 - x^5). - Colin Barker, Jul 25 2018

EXAMPLE

All solutions for n=3: