OFFSET
5,2
EXAMPLE
a(6)=4 because b(6=2^1*3^1)=7, b(7=7^1)=8, b(8=2^3)=5, so we apply b(m) 3 times to get 5.
MATHEMATICA
f[n_] := Sum[FactorInteger[n][[i]][[1]] + FactorInteger[n][[i]][[2]], { i, Length[FactorInteger[n]]}] g[t_, n_] := If[t == 1, n, f[g[t - 1, n]]]; a[n_] := Position[Array[g[ #, n] &, 100], 5, {1}, 1][[1, 1]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Y. Kallus (yoav(AT)rice.edu), Aug 29 2005
STATUS
approved