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%I #8 Jul 10 2018 05:55:08
%S 1,2,5,10,21,46,97,207,437,920,1941,4090,8630,18217,38456,81197,
%T 171420,361878,763917,1612552,3403944,7185413,15167839,32018305,
%U 67588649,142675574,301179445,635771007,1342072303,2833028679,5980341655
%N Number of n X 1 0..2 arrays with every element value z a city block distance of exactly z from another element value z.
%C Column 1 of A209476.
%H R. H. Hardin, <a href="/A209469/b209469.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - a(n-4) + 4*a(n-5) - 3*a(n-6) + 3*a(n-7) + a(n-8) - 2*a(n-9) + a(n-10) - a(n-11).
%F Empirical g.f.: x*(1 + x + x^2)*(1 - 2*x + 2*x^2 - x^3 + x^4 + x^5 - x^6 + x^7 - x^8) / (1 - 3*x + 2*x^2 + x^4 - 4*x^5 + 3*x^6 - 3*x^7 - x^8 + 2*x^9 - x^10 + x^11). - _Colin Barker_, Jul 10 2018
%e Some solutions for n=8:
%e ..0....0....1....0....0....0....2....1....0....2....0....1....0....0....2....0
%e ..0....2....1....1....0....0....2....1....0....2....1....1....0....0....0....1
%e ..0....0....1....1....0....1....2....0....1....2....1....0....2....0....2....1
%e ..1....2....1....1....0....1....2....2....1....2....2....0....2....1....0....0
%e ..1....0....0....1....0....0....2....0....1....0....0....0....2....1....0....0
%e ..0....1....0....0....0....1....1....2....0....1....2....0....2....2....1....0
%e ..1....1....1....1....0....1....1....0....1....1....1....0....1....0....1....0
%e ..1....0....1....1....0....1....0....2....1....1....1....0....1....2....0....0
%Y Cf. A209476.
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 09 2012
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