A083534 First difference sequence of A007617. Difference between consecutive values not being in the range of phi[A000010].

2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 2, 2, 2

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Formula

a(n)=A007617[n+1]-A007617[n]

Example

a(n) is either 2 or 1 since odd numbers are in A007619;
if a(n)=1 then A007619[n+1] is an even number not in
range of phi; n={11,13,14,15,17} are not in the range of
phi and the corresponding differences are {2,1,1,2}.

Mathematica

t0[x_] := Table[j, {j, 1, x}] t=Table[EulerPhi[w], {w, 1, 10000}]; u=Union[%]; c=Complement[t0[10000], u]; Delete[c-RotateRight[c], 1]

Prog

(Haskell)
a083534 n = a083534_list !! (n-1)
a083534_list = zipWith (-) (tail a007617_list) a007617_list
-- Reinhard Zumkeller, Nov 26 2015

Crossrefs

Cf. A000010, A007617, A002202, A005277, A083531-A083536, A005277.

Sequence in context: A237348 A037813 A159700 * A174664 A027386 A102300

Adjacent sequences: A083531 A083532 A083533 * A083535 A083536 A083537

Keyword

nonn

Author

Labos Elemer, May 20 2003

Status

approved