A183547 - OEIS

%I #9 Mar 29 2018 13:33:00

%S 3,15,71,299,1325,5845,25785,113841,502523,2218399,9793287,43233099,

%T 190855613,842545925,3719480233,16419916497,72486917979,319998782959,

%U 1412657953559,6236281512443,27530519336653,121535484480133

%N Number of n X 2 0..2 arrays with each element equal to either the maximum or the minimum of its horizontal and vertical neighbors.

%C Column 2 of A183554.

%H R. H. Hardin, <a href="/A183547/b183547.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 5*a(n-1) - 3*a(n-2) + 4*a(n-3) - 9*a(n-4) - 13*a(n-6) + 8*a(n-7) + 4*a(n-8) + 7*a(n-9) + 2*a(n-10).

%F Empirical g.f.: x*(3 + 5*x^2 - 23*x^3 + 10*x^4 - 32*x^5 + 17*x^6 + 13*x^7 + 9*x^8 + 10*x^9) / (1 - 5*x + 3*x^2 - 4*x^3 + 9*x^4 + 13*x^6 - 8*x^7 - 4*x^8 - 7*x^9 - 2*x^10). - _Colin Barker_, Mar 29 2018

%e Some solutions for 3 X 2:

%e ..0..0....2..2....1..1....2..2....1..1....0..0....2..1....1..1....0..0....2..2

%e ..1..0....1..2....2..1....0..0....0..1....1..1....2..1....0..0....2..0....0..2

%e ..1..1....1..1....2..1....1..1....0..1....1..1....2..1....1..1....2..0....0..2

%Y Cf. A183554.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 05 2011