OFFSET
1,2
MATHEMATICA
PrimeFactors[n_Integer] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; a[1] = 1; a[n_] := a[n] = (Plus @@ (a[ # ] & /@ PrimePi[ PrimeFactors[n]])); b = Table[0, {12}]; Do[c = a[n]; If[ b[[c]] == 0, b[[c]] = n]], {n, 11500000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, May 04 2004
STATUS
approved