A258547 - OEIS

%I #6 Oct 14 2020 12:36:40

%S 16,44,104,228,480,988,2008,4052,8144,16332,32712,65476,131008,262076,

%T 524216,1048500,2097072,4194220,8388520,16777124,33554336,67108764,

%U 134217624,268435348,536870800,1073741708,2147483528,4294967172

%N Number of (n+1)X(1+1) 0..1 arrays with every 2X2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically

%C Column 1 and row 1 of A258554

%H R. H. Hardin, <a href="/A258547/b258547.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3)

%F a(n) = 16*2^n - 4*n - 12. - _Michael Somos_, Oct 14 2020

%e Some solutions for n=4

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

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

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

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

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

%o (PARI) {a(n) = if(n<-2, 0, 16*2^n - 4*n - 12)}; /* _Michael Somos_, Oct 14 2020 */

%Y Cf. A258554

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 03 2015