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A185469 Number of (n+2)X3 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order.

%I A185469 #7 Jul 22 2025 09:47:50
%S A185469 1169,4594,13659,34779,79743,169052,336690,636698,1151966,2005704,
%T A185469 3376100,5514721,8769262,13611298,20669745,30770788,44985087,64683126,
%U A185469 91599625,127907991,176305841,240112688,323380940,431021422,568944692
%N A185469 Number of (n+2)X3 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order.
%C A185469 Column 1 of A185477
%H A185469 R. H. Hardin, <a href="/A185469/b185469.txt">Table of n, a(n) for n = 1..200</a>
%F A185469 Empirical: a(n) = (1/362880)*n^9
%F A185469 + (1/1008)*n^8
%F A185469 + (431/12096)*n^7
%F A185469 + (373/720)*n^6
%F A185469 + (82453/17280)*n^5
%F A185469 + (637/18)*n^4
%F A185469 + (2819461/18144)*n^3
%F A185469 + (119729/315)*n^2
%F A185469 + (605807/1260)*n
%F A185469 + 112
%e A185469 Some solutions for 4X3
%e A185469 ..1..1..2....0..1..2....0..0..0....0..1..2....0..0..1....0..0..0....0..0..2
%e A185469 ..1..1..2....0..1..2....0..0..2....0..1..2....0..1..1....0..0..2....0..2..2
%e A185469 ..1..2..1....0..1..2....0..2..1....1..1..0....0..2..2....0..1..0....1..0..1
%e A185469 ..2..0..1....2..1..2....2..0..0....2..0..1....1..0..1....0..2..0....2..0..2
%K A185469 nonn
%O A185469 1,1
%A A185469 _R. H. Hardin_ Jan 28 2011