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%I #9 Feb 27 2015 10:51:09
%S 1,1,1,1,2,3,4,6,9,13,17,27,31,42,57,83,104
%N 1/n! times the number of ordered pairs of permutation functions f,g on n elements where f(g(g(x))) = g(f(f(x))).
%C The fact that A239836(n) is a multiple of n! follows from a general result in group theory due to Solomon.
%H L. Solomon, <a href="http://dx.doi.org/10.1007/BF01899292">The solutions of equations in groups</a>, Arch. Math., V.20. no.3, (1969) 241-247.
%F a(n) = A239836(n)/n!.
%Y Cf. A239836.
%K nonn,more
%O 0,5
%A _Paul Boddington_, Feb 24 2015