A081758 Sum of prime factors (with repetition) of sum of prime factors (with repetition) of n.

2, 3, 4, 5, 5, 7, 5, 5, 7, 11, 7, 13, 6, 6, 6, 17, 6, 19, 6, 7, 13, 23, 6, 7, 8, 6, 11, 29, 7, 31, 7, 9, 19, 7, 7, 37, 10, 8, 11, 41, 7, 43, 8, 11, 10, 47, 11, 9, 7, 9, 17, 53, 11, 8, 13, 13, 31, 59, 7, 61, 14, 13, 7, 8, 8, 67, 10, 15, 9, 71, 7, 73, 16, 13, 23, 8, 8, 79, 13, 7, 43, 83, 9, 13, 11

Offset

2,1

Comments

a(n) = A001414(A001414(n)). For further iterations see: A029908, A002217;

a(n)=n iff n is prime or 4.

Links

Table of n, a(n) for n=2..86.

Example

18 = 2*3*3 -> 2+3+3 = 2*2*2 -> 2+2+2 = 6: a(18) = 6.

Crossrefs

Sequence in context: A345303 A345310 A029908 * A106492 A338038 A112264

Adjacent sequences: A081755 A081756 A081757 * A081759 A081760 A081761

Keyword

nonn

Author

Reinhard Zumkeller, Apr 08 2003

Status

approved