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%I #8 Aug 16 2018 13:22:59
%S 2,7,34,389,7145,179465,5426201,180390761,6268113977,222151991177,
%T 7942488470873,285058950003113,10248273625735289,368717006467136969,
%U 13270285321513993625,477673900318354951145,17195359005212203140281
%N Number of n X 2 0..7 arrays with no element equal to another at a city block distance of exactly two, and new values 0..7 introduced in row major order.
%C Column 2 of A222894.
%H R. H. Hardin, <a href="/A222891/b222891.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 66*a(n-1) - 1353*a(n-2) + 10648*a(n-3) - 30096*a(n-4) + 20736*a(n-5) for n>7.
%F Empirical g.f.: x*(2 - 125*x + 2278*x^2 - 13680*x^3 + 13129*x^4 + 41380*x^5 - 15264*x^6) / ((1 - x)*(1 - 4*x)*(1 - 9*x)*(1 - 16*x)*(1 - 36*x)). - _Colin Barker_, Aug 16 2018
%e Some solutions for n=3:
%e ..0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..1....0..1....0..1
%e ..2..3....1..2....1..1....0..1....2..1....2..3....2..3....2..3....2..1....2..3
%e ..2..3....3..3....2..2....2..3....2..3....1..3....4..5....1..0....3..4....4..0
%Y Cf. A222894.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 08 2013
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