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 A093320 a(1) = 1; for m >= 2, a(m) = sum{p|m} a(pi(p)), where the sum is over the distinct prime divisors p of m and pi(p) is the order of p among the primes = the number of primes <= p. 2
 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 3, 1, 2, 2, 3, 1, 1, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 1, 2, 2, 3, 1, 2, 2, 2, 2, 3, 1, 3, 2, 2, 2, 1, 3, 3, 1, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 4, 2, 2, 1, 3, 1, 3, 2, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 2, 1, 2, 2, 2, 3, 3, 1, 3, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS MATHEMATICA PrimeFactors[n_Integer] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; a[1] = 1; a[n_] := a[n] = (Plus @@ (a[ # ] & /@ PrimePi[ PrimeFactors[n]])); Table[ a[n], {n, 105}] (* Robert G. Wilson v, May 04 2004 *) CROSSREFS Cf. A093321, A066328, A094162 (for where n first appears). Sequence in context: A025909 A025899 A025869 * A082370 A005136 A138474 Adjacent sequences:  A093317 A093318 A093319 * A093321 A093322 A093323 KEYWORD nonn,easy AUTHOR Leroy Quet, Apr 26 2004 EXTENSIONS More terms from Robert G. Wilson v, May 04 2004 STATUS approved

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Last modified July 20 15:59 EDT 2019. Contains 325185 sequences. (Running on oeis4.)