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1/2 the number of colorings of a 3 X 3 square array with n colors.
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%I #17 Dec 23 2014 19:50:34

%S 1,123,4806,71410,583455,3232341,13675228,47502036,141991245,

%T 377162335,910842306,2033854758,4253012491,8411348505,15856955640,

%U 28673921896,49991146713,84387303171,138412872190,221253017370,345558093111,528471784093,792890261076

%N 1/2 the number of colorings of a 3 X 3 square array with n colors.

%H Alois P. Heinz, <a href="/A068239/b068239.txt">Table of n, a(n) for n = 2..1000</a>

%F From _Alois P. Heinz_, Apr 27 2012: (Start)

%F G.f.: x^2*(1199*x^7 +16567*x^6 +60099*x^5 +71075*x^4 +28765*x^3 +3621*x^2 +113*x+1) / (x-1)^10.

%F a(n) = (79*n -323*n^2 +594*n^3 -648*n^4 +459*n^5 -216*n^6 +66*n^7 -12*n^8 +n^9) / 2.

%F (End)

%p a:= n-> (79+(-323+(594+(-648+(459+(-216+(66+(-12+n)*n)*n) *n)*n)*n)*n)*n) *n/2:

%p seq(a(n), n=2..30); # _Alois P. Heinz_, Apr 27 2012

%Y Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

%K nonn

%O 2,2

%A _R. H. Hardin_, Feb 24 2002