2,1

Table of n, a(n) for n=2..105.

If p_1*p_2*p_3* ... *p_m=n is the unique prime factorization of n, then a(n)=sum{1<=k<=m, ds_3(p_k)}, where ds_3 is the digital sum base 3.

a(6)=3, since 6=2*3 and so a(6)=ds_3(2)+ds_3(3)=2+1.

Cf. A007953, A118503, A080773.

Sequence in context: A304573 A094322 A136757 * A117235 A159573 A102916

Adjacent sequences: A134596 A134597 A134598 * A134600 A134601 A134602

nonn,base

Hieronymus Fischer, Nov 11 2007

approved