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%I #16 Mar 12 2015 12:17:31
%S 1,1,4,18,168,1560,20880,267120,5080320,93623040,2184537600,
%T 49896000000,1451853849600,41739720422400,1426847092070400,
%U 47989033956864000,1919268439216128000,76229151152394240000,3471527082588364800000,156226856133456396288000
%N Number of ordered pairs of permutation functions on n elements satisfying f(f(f(x))) = g(f(g(x))).
%H Hiroaki Yamanouchi, <a href="/A239839/b239839.txt">Table of n, a(n) for n = 0..60</a>
%Y Cf. A000012, A000085, A000142, A088311, A053529, A001044.
%K nonn
%O 0,3
%A _Chad Brewbaker_, Mar 27 2014
%E a(8)-a(9) from _Giovanni Resta_, Mar 27 2014
%E a(10)-a(13) from _Paul Boddington_, Feb 23 2015
%E a(14)-a(19) from _Hiroaki Yamanouchi_, Mar 12 2015
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