A250775 - OEIS

%I #8 Nov 19 2018 09:13:52

%S 576,1026,1622,2396,3412,4798,6810,9960,15272,24794,42622,76948,

%T 144156,277014,541058,1067360,2118064,4217458,8414118,16805196,

%U 33584996,67142126,134253802,268474456,536912952,1073787018,2147532110,4295019140

%N Number of (7+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

%H R. H. Hardin, <a href="/A250775/b250775.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4); a(n) = 32*2^(n-1) + 57*n^2 + 247*n + 240.

%F Empirical g.f.: 2*x*(288 - 927*x + 838*x^2 - 256*x^3) / ((1 - x)^3*(1 - 2*x)). - _Colin Barker_, Nov 19 2018

%e Some solutions for n=4:

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

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

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

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

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

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

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

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

%Y Row 7 of A250769.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 27 2014