OFFSET
2,1
FORMULA
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.
EXAMPLE
a(6)=3, since 6=2*3 and so a(6)=ds_3(2)+ds_3(3)=2+1.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Hieronymus Fischer, Nov 11 2007
STATUS
approved