A258553 - OEIS

%I #8 Dec 22 2018 07:29:06

%S 2008,894,2542,4313,8612,13833,21653,31254,43655,57928,75822,96565,

%T 121226,148915,181429,218044,259877,306086,358516,416491,481176,

%U 551777,630187,715778,809763,911396,1022618,1142849,1273350,1413423,1565057

%N Number of (n+1) X (7+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="/A258553/b258553.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>15.

%F Empirical g.f.: x*(2008 - 7138*x + 11014*x^2 - 8523*x^3 + 3036*x^4 + 3127*x^5 - 7731*x^6 + 6028*x^7 - 3207*x^8 + 2064*x^9 - 606*x^10 - 26*x^11 + 4*x^12 - 12*x^13 + 10*x^14) / ((1 - x)^5*(1 + x)*(1 + x^2)). - _Colin Barker_, Dec 22 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 7 of A258554.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 03 2015