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1/5 the number of colorings of an n X n square array with 5 colors.
3

%I #17 Sep 23 2019 06:39:41

%S 1,52,28564,165770032,10164078082036,6584229526795818280,

%T 45062665956031451017237456,3258395057698765483724093981321824,

%U 2489232886416012985921659124731697904597044,20091032492258710696689787524926465967570325433558752

%N 1/5 the number of colorings of an n X n square array with 5 colors.

%H Jean-François Alcover, <a href="/A068255/b068255.txt">Table of n, a(n) for n = 1..14</a>

%t A222144 = Cases[Import["https://oeis.org/A222144/b222144.txt", "Table"], {_, _}][[All, 2]];

%t a[n_] := A222144[[2 n^2 - 2 n + 1]];

%t Table[a[n], {n, 1, 14}] (* _Jean-François Alcover_, Sep 23 2019 *)

%Y Main diagonal of A222144.

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

%K nonn

%O 1,2

%A _R. H. Hardin_, Feb 24 2002

%E a(8)-a(10) from _Alois P. Heinz_, Apr 27 2012