A217978 - OEIS

%I #7 Jul 23 2018 15:46:17

%S 6,6,36,98,362,1180,4046,13594,46052,155494,525730,1776548,6004634,

%T 20293538,68587432,231806206,783444274,2647830256,8948960354,

%U 30245088582,102220312680,345477304222,1167620873294,3946246173440,13337256366382

%N Number of n X 4 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random 0..1 n X 4 array.

%C Column 4 of A217982.

%H R. H. Hardin, <a href="/A217978/b217978.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 5*a(n-2) + a(n-3) - 5*a(n-4) - 8*a(n-5) + a(n-6) + 2*a(n-7).

%F Empirical g.f.: 2*x*(3 - 3*x - 3*x^2 - 5*x^3 + 5*x^4 + 4*x^5) / (1 - 2*x - 5*x^2 - x^3 + 5*x^4 + 8*x^5 - x^6 - 2*x^7). - _Colin Barker_, Jul 23 2018

%e Some solutions for n=3:

%e ..1..1..0..0....0..0..0..1....1..1..1..1....0..0..1..1....1..0..0..0

%e ..0..0..0..0....0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..0

%e ..0..0..1..1....1..0..0..0....0..0..0..1....1..0..0..0....0..0..0..0

%Y Cf. A217982.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 16 2012