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A220155 Number of 3Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 3Xn array.

%I A220155 #6 Jul 23 2025 00:54:03
%S A220155 10,26,77,254,645,1413,2841,5412,9905,17565,30369,51437,85641,140477,
%T A220155 227277,362851,571663,888660,1362889,2062054,3078183,4534594,6594369,
%U A220155 9470566,13438421,18849815,26150305,35899043,48791933,65688403,87642197
%N A220155 Number of 3Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 3Xn array.
%C A220155 Row 3 of A220153
%H A220155 R. H. Hardin, <a href="/A220155/b220155.txt">Table of n, a(n) for n = 1..210</a>
%F A220155 Empirical: a(n) = (1/362880)*n^9 + (1/40320)*n^8 - (11/60480)*n^7 - (49/2880)*n^6 + (10837/17280)*n^5 - (30473/5760)*n^4 + (1003267/45360)*n^3 + (41353/3360)*n^2 - (594077/2520)*n + 361 for n>6
%e A220155 Some solutions for n=3
%e A220155 ..2..0..0....1..0..1....1..1..1....0..0..1....1..0..0....1..0..0....0..0..0
%e A220155 ..2..0..0....1..0..0....1..1..1....0..0..0....2..2..1....2..1..1....2..1..0
%e A220155 ..2..0..0....2..2..1....2..1..1....1..1..0....2..2..2....2..2..2....2..1..1
%K A220155 nonn
%O A220155 1,1
%A A220155 _R. H. Hardin_ Dec 06 2012