A102304 Sum of factors of numbers having exactly three prime factors.

6, 7, 8, 9, 9, 11, 10, 12, 15, 11, 12, 17, 13, 16, 21, 14, 13, 23, 18, 27, 16, 17, 22, 15, 18, 24, 33, 19, 35, 15, 20, 28, 17, 41, 23, 20, 45, 19, 24, 25, 47, 34, 17, 22, 36, 51, 26, 21, 29, 57, 42, 30, 21, 63, 26, 24, 65, 19, 46, 25, 48, 35, 28, 71, 23, 21, 37, 52, 75, 27, 26

Offset

0,1

Comments

a(n) = A001414(A014612(n)).

Prime factors are counted with multiplicity, e.g., 20 has three prime factors: 2 x 2 x 5. [From Harvey P. Dale, Oct 04 2011]

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

A014612(25) = 114 = 2*3*19 -> 2+3+19 = 24 = a(25).

Mathematica

Total[Times@@@FactorInteger[#]]&/@Select[Range[300], PrimeOmega[#]==3&] (* Harvey P. Dale, Oct 04 2011 *)

Crossrefs

Sequence in context: A324031 A248418 A168679 * A114459 A168096 A030546

Adjacent sequences: A102301 A102302 A102303 * A102305 A102306 A102307

Keyword

nonn

Author

Reinhard Zumkeller, Feb 20 2005

Status

approved