cp's OEIS Frontend

A250677 Number of (1+1) X (n+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 A250677 #11 Mar 19 2018 22:09:07
%S A250677 104,669,3927,22119,120233,637948,3321772,17052553,86573591,435717423,
%T A250677 2177845221,10825761528,53576004128,264200974309,1299108852679,
%U A250677 6372932446759,31203614429489,152543921033076,744788303718996
%N A250677 Number of (1+1) X (n+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 A250677 Row 1 of A250676.
%H A250677 R. H. Hardin, <a href="/A250677/b250677.txt">Table of n, a(n) for n = 1..210</a>
%F A250677 Empirical: a(n) = 10*a(n-1) - 21*a(n-2) - 54*a(n-3) + 155*a(n-4) + 118*a(n-5) - 228*a(n-6) - 144*a(n-7).
%F A250677 Empirical g.f.: x*(104 - 371*x - 579*x^2 + 2514*x^3 + 1516*x^4 - 3792*x^5 - 2304*x^6) / ((1 - 4*x)*(1 - x - x^2)*(1 - 2*x - 4*x^2)*(1 - 3*x - 9*x^2)). - _Colin Barker_, Mar 19 2018
%e A250677 Some solutions for n=4:
%e A250677   2 1 3 1 1    1 2 1 0 1    1 2 2 0 0    1 1 1 1 3
%e A250677   3 2 2 3 3    1 3 2 1 2    2 3 1 1 1    1 2 3 3 1
%Y A250677 Cf. A250676.
%K A250677 nonn
%O A250677 1,1
%A A250677 _R. H. Hardin_, Nov 26 2014