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 A019269 Let Dedekind's psi(m) = product of (p+1)p^(e-1) for primes p, where p^e is a factor of m. Iterating psi(m) eventually results in a number of form 2^a*3^b. a(n) is the number of steps to reach such a number. 3
 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 2, 1, 1, 0, 1, 0, 2, 1, 1, 1, 1, 0, 2, 2, 0, 1, 2, 1, 1, 0, 1, 1, 1, 0, 3, 2, 2, 1, 2, 1, 2, 1, 1, 1, 1, 0, 2, 2, 1, 2, 1, 0, 1, 1, 2, 2, 2, 1, 2, 1, 1, 0, 2, 1, 2, 1, 1, 1, 1, 0, 4, 3, 2, 2, 1, 2, 2, 1, 0, 2, 2, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 1, 2, 0, 3, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,13 COMMENTS a(A019268(n)) = n and a(m) <> n for m < A019268(n). [Reinhard Zumkeller, Apr 12 2012] REFERENCES R. K. Guy, "Unsolved Problems in Number Theory", section B41. Peter Giblin, "Primes and Programming - an Introduction to Number Theory with Computation", page 118. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 PROG (Haskell) a019269 n = snd \$ until ((== 1) . a065333 . fst)                         (\(x, i) -> (a001615 x, i+1)) (n, 0) -- Reinhard Zumkeller, Apr 12 2012 CROSSREFS Cf. A001615, A065333. Sequence in context: A257510 A225721 A040076 * A204459 A035155 A090584 Adjacent sequences:  A019266 A019267 A019268 * A019270 A019271 A019272 KEYWORD nonn AUTHOR STATUS approved

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