A235883 - OEIS

A235883

Number of (n+1) X (7+1) 0..2 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.

%I #7 Oct 19 2018 09:28:05

%S 7329,8871,11973,18231,30909,56751,109893,220551,454989,963231,

%T 2097813,4721271,11031069,26839311,68021733,179084391,487303149,

%U 1362020991,3886297653,11259373911,32979095229,97339244271,288821661573

%N Number of (n+1) X (7+1) 0..2 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.

%H R. H. Hardin, <a href="/A235883/b235883.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3).

%F Conjectures from _Colin Barker_, Oct 19 2018: (Start)

%F G.f.: 3*x*(2443 - 11701*x + 13122*x^2) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).

%F a(n) = 3*(1932 + 127*2^(1+n) + 3^n).

%F (End)

%e Some solutions for n=5:

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

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

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

%Y Column 7 of A235884.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 16 2014