OFFSET
1,7
COMMENTS
a(n) >= A256757(n) - 1.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
FORMULA
For n > 1, a(n) = a(A053575(n)) + 1.
EXAMPLE
a(18) = 2 because it takes two steps to reach 1 from 18: phi(18) = 6, the odd part of which is 3, and phi(3) = 2, the odd part of which is 1.
a(19) = 3 because it takes three steps to reach 1 from 19: phi(19) = 18, the odd part of which is 9, and phi(9) = 6, the odd part of which is 3, and phi(3) = 2, the odd part of which is 1.
MATHEMATICA
oddPhi[n_] := Module[{phi = EulerPhi[n]}, phi/2^IntegerExponent[phi, 2]]; Table[Length[NestWhileList[oddPhi[#] &, n, # > 1 &]] - 1, {n, 100}] (* T. D. Noe, Oct 07 2013 *)
PROG
(Haskell)
a227944 n = fst $
until ((== 1) . snd) (\(i, x) -> (i + 1, a053575 x)) (0, n)
-- Reinhard Zumkeller, Oct 09 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Max Alekseyev, Oct 03 2013
STATUS
approved