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A250670 Number of (n+1)X(2+1) 0..3 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.

%I A250670 #6 Jul 23 2025 12:39:55
%S A250670 669,5154,34630,210158,1185860,6325144,32230991,158164928,752162284,
%T A250670 3484008326,15783790118,70176461116,307081524576,1325658002144,
%U A250670 5657123014959,23904700805062,100166248075189,416720321036830
%N A250670 Number of (n+1)X(2+1) 0..3 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.
%C A250670 Column 2 of A250676
%H A250670 R. H. Hardin, <a href="/A250670/b250670.txt">Table of n, a(n) for n = 1..210</a>
%F A250670 Empirical: a(n) = 38*a(n-1) -678*a(n-2) +7552*a(n-3) -58895*a(n-4) +341814*a(n-5) -1531840*a(n-6) +5427992*a(n-7) -15445215*a(n-8) +35639986*a(n-9) -67056686*a(n-10) +103057344*a(n-11) -129153505*a(n-12) +131275346*a(n-13) -107173068*a(n-14) +69203560*a(n-15) -34519952*a(n-16) +12821856*a(n-17) -3336768*a(n-18) +542592*a(n-19) -41472*a(n-20) for n>28
%e A250670 Some solutions for n=3
%e A250670 ..1..0..2....2..1..1....0..0..2....2..0..1....3..0..1....3..1..1....1..0..2
%e A250670 ..1..0..3....2..1..1....0..1..1....1..1..2....3..0..2....3..1..1....0..1..1
%e A250670 ..2..2..1....2..1..3....0..1..2....1..1..2....3..2..0....3..2..0....0..2..2
%e A250670 ..3..1..3....2..1..3....1..3..0....1..1..3....2..3..1....3..2..3....1..1..3
%K A250670 nonn
%O A250670 1,1
%A A250670 _R. H. Hardin_, Nov 26 2014