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%I #11 Apr 24 2017 10:00:26
%S 1,6,7,8,9,455,457,458,459,461,8167302,8167314,8167315,8167316,
%T 8167328,8167330,8167335,8167336,8167346,8167347,8167348,8167350,
%U 8167351,8167352,8167410,8167413
%N Values of n for which A013939(n)/n is an integer.
%C For 455, 457, 458, 459, 461 the quotient is 2. The cause of "step-like" appearance of terms is that the next integer is reached slowly with the summatory function A013939. Next "island" is expected above 500000. Similar phenomenon is observable in the analogous A050226 sequence too.
%C The quotients for "3rd island" after 8160000 equal 3. (Sep 21 2001)
%C a(27) > 10^13. - _Giovanni Resta_, Apr 24 2017
%t s = 0; Do[s = s + Length[FactorInteger[n]]; If[IntegerQ[s/n], Print[n]], {n, 1, 10000000}]
%Y Cf. A013939, A050226, A001221, A064612.
%K nonn
%O 1,2
%A _Labos Elemer_, Sep 05 2001
%E More terms from _Robert G. Wilson v_, Sep 19 2001