A063971 Values of n for which A013939(n)/n is an integer.

1, 6, 7, 8, 9, 455, 457, 458, 459, 461, 8167302, 8167314, 8167315, 8167316, 8167328, 8167330, 8167335, 8167336, 8167346, 8167347, 8167348, 8167350, 8167351, 8167352, 8167410, 8167413

Offset: 1

Author

Labos Elemer, Sep 05 2001

Keywords

• nonn

Comments

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.

The quotients for "3rd island" after 8160000 equal 3. (Sep 21 2001)

a(27) > 10^13. - Giovanni Resta, Apr 24 2017

Crossrefs

Cf. A013939, A050226, A001221, A064612.

Programs

Mathematica

s = 0; Do[s = s + Length[FactorInteger[n]]; If[IntegerQ[s/n], Print[n]], {n, 1, 10000000}]

Extensions

More terms from Robert G. Wilson v, Sep 19 2001