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A083533 First difference sequence of A002202. Difference between consecutive possible values for phi[n]. 0
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; internal format)
OFFSET

1,2

FORMULA

a(n)=A002202[n+1]-A02202[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]

CROSSREFS

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

Sequence in context: A064770 A060467 A125918 * A076500 A060594 A104361

Adjacent sequences:  A083530 A083531 A083532 * A083534 A083535 A083536

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), May 20 2003

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.