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A250690 Number of (n+1)X(7+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 A250690 #6 Jul 23 2025 12:41:56
%S A250690 780551,3894542,19218493,92169818,420283865,1832718604,7662909389,
%T A250690 30911828018,121133941641,463951270668,1745661462155,6479480240674,
%U A250690 23806631357499,86830525247352,315154449951319,1140724783380058
%N A250690 Number of (n+1)X(7+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 A250690 Column 7 of A250691
%H A250690 R. H. Hardin, <a href="/A250690/b250690.txt">Table of n, a(n) for n = 1..33</a>
%F A250690 Empirical: a(n) = 27*a(n-1) -331*a(n-2) +2439*a(n-3) -12049*a(n-4) +42129*a(n-5) -107225*a(n-6) +201069*a(n-7) -277706*a(n-8) +278928*a(n-9) -197984*a(n-10) +94032*a(n-11) -26784*a(n-12) +3456*a(n-13) for n>17
%e A250690 Some solutions for n=1
%e A250690 ..0..2..0..1..2..2..3..1....0..0..2..1..2..3..0..1....0..0..0..0..2..1..0..1
%e A250690 ..0..2..0..1..2..2..3..1....0..0..2..1..2..3..0..2....0..0..0..1..3..2..2..3
%K A250690 nonn
%O A250690 1,1
%A A250690 _R. H. Hardin_, Nov 26 2014