A218078 - OEIS

A218078

Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..1 n X 2 array.

2, 4, 8, 18, 38, 82, 176, 378, 812, 1744, 3746, 8046, 17282, 37120, 79730, 171252, 367832, 790066, 1696982, 3644946, 7828976, 16815850, 36118748, 77579424, 166632770, 357910366, 768755330, 1651208832, 3546629858, 7617802852

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OFFSET

1,1

COMMENTS

Column 2 of A218084.

LINKS

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

Todd Mullen, On Variants of Diffusion, Dalhousie University (Halifax, NS Canada, 2020).

FORMULA

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

Empirical g.f.: 2*x*(1 + x) / (1 - x - 2*x^2 - x^3). - Colin Barker, Jul 24 2018

EXAMPLE

All solutions for n=3:

..1..1....0..0....0..0....1..1....0..0....0..0....1..0....1..1

..0..0....0..0....0..0....1..0....0..0....0..1....0..0....1..1

..0..0....1..1....0..0....0..0....0..1....1..1....0..0....1..1

CROSSREFS

Cf. A218084.

Sequence in context: A220839 A288206 A371791 * A110110 A300221 A233437

Adjacent sequences: A218075 A218076 A218077 * A218079 A218080 A218081

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 20 2012

STATUS

approved