A258548 - OEIS

%I #8 Dec 21 2018 15:01:20

%S 44,112,296,652,1329,2530,4667,8419,14932,26184,45561,78903,136170,

%T 234461,403075,692272,1188185,2038466,3496239,5995441,10279967,

%U 17625041,30216773,51802782,88807568,152244537,260993810,447421309,767011467

%N Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.

%H R. H. Hardin, <a href="/A258548/b258548.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 3*a(n-4) - 4*a(n-5) + 2*a(n-6) + 2*a(n-7) - 3*a(n-8) + a(n-9) for n>11.

%F Empirical g.f.: x*(44 - 64*x + 68*x^2 - 16*x^3 - 43*x^4 + 18*x^5 + 12*x^6 - 12*x^7 - 2*x^8 + 6*x^9 - x^10) / ((1 - x)^3*(1 - x - x^2 - x^4 + x^6)). - _Colin Barker_, Dec 21 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A258554.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 03 2015