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%I #7 Jan 10 2013 07:15:51
%S 1,4,16,92,665,5257,44705,394240,3558181,32608999,302172507,2823898245
%N Number of refactorable numbers (A033950) <= 10^n.
%C Simon Colton conjectures that the number of refactorables less than x is at least x/(2 log(x)).
%H S. Colton, <a href="http://www.cs.uwaterloo.ca/journals/JIS/colton/joisol.html">Refactorable Numbers - A Machine Invention</a>, J. Integer Sequences, Vol. 2, 1999, #2.
%t c = 0; k = 1; Do[ While[k <= 10^n, If[ Mod[k, DivisorSigma[0, k]] == 0, c++ ]; k++ ]; Print[c], {n, 0, 8}]
%Y Cf. A033950.
%K more,nonn
%O 0,2
%A _Robert G. Wilson v_, Nov 01 2005
%E a(9)-a(11) from _Donovan Johnson_, Sep 19 2009