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%I #10 Jul 21 2018 10:07:09
%S 2,17,50,107,194,317,482,695,962,1289,1682,2147,2690,3317,4034,4847,
%T 5762,6785,7922,9179,10562,12077,13730,15527,17474,19577,21842,24275,
%U 26882,29669,32642,35807,39170,42737,46514,50507,54722,59165,63842,68759,73922
%N Number of 0..n arrays of length 3 with 0 never adjacent to n.
%C Row 2 of A212835.
%H R. H. Hardin, <a href="/A212836/b212836.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = n^3 + 3*n^2 - n - 1.
%F Conjectures from _Colin Barker_, Jul 21 2018: (Start)
%F G.f.: x*(2 + 9*x - 6*x^2 + x^3) / (1 - x)^4.
%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.
%F (End)
%e Some solutions for n=5:
%e ..4....1....2....5....0....3....4....2....4....0....2....5....4....3....1....1
%e ..4....2....4....1....3....5....2....1....3....0....4....4....4....2....3....2
%e ..2....1....3....5....3....1....4....4....5....3....2....3....1....2....0....0
%Y Cf. A212835.
%K nonn
%O 1,1
%A _R. H. Hardin_, May 28 2012
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