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 A083533 First difference sequence of A002202. Difference between consecutive possible values for phi(n). 10
 1, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 4, 2, 2, 4, 4, 2, 2, 2, 2, 4, 2, 2, 2, 2, 4, 2, 4, 2, 6, 2, 2, 2, 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 4, 4, 6, 2, 2, 2, 4, 2, 2, 4, 4, 2, 6, 4, 2, 2, 2, 2, 4, 4, 2, 2, 4, 6, 2, 4, 2, 2, 4, 4, 2, 2, 4, 4, 2, 2, 2, 2, 4, 6, 2, 10, 2, 4, 4, 2, 2, 4, 2, 2, 4, 4, 2, 6, 4, 2, 2, 4, 6, 4, 2, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A002202(n+1) - A002202(n). EXAMPLE 12 and 16 are the 7th and 8th possible totient values 12 = phi(13), 16 = phi(17), while {13,14,15} are impossible ones; thus 16 - 12 = 4 = a(7) = A002202(8) - A002202(7). MATHEMATICA t=Table[EulerPhi[w], {w, 1, 25000}]; u=Union[%]; Delete[u-RotateRight[u], 1] PROG (Haskell) a083533 n = a083533_list !! (n-1) a083533_list = zipWith (-) (tail a002202_list) a002202_list -- Reinhard Zumkeller, Nov 26 2015 CROSSREFS Cf. A000010, A002202, A005277, A083531, A083532, A083534, A083535, A083536, A005277. Sequence in context: A060467 A125918 A239202 * A076500 A060594 A327813 Adjacent sequences:  A083530 A083531 A083532 * A083534 A083535 A083536 KEYWORD nonn AUTHOR Labos Elemer, May 20 2003 STATUS approved

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Last modified May 24 23:45 EDT 2020. Contains 334581 sequences. (Running on oeis4.)