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A065395 Commutator of sigma and phi functions. +0
11
0, -1, 1, -3, 5, -1, 8, -1, 0, 1, 14, -5, 22, 4, 7, -15, 25, -12, 31, 3, 12, 6, 28, -1, 12, 16, 23, 4, 48, -9, 56, -5, 26, 13, 44, -44, 73, 23, 36, 7, 78, -4, 76, 18, 36, 12, 56, -29, 60, -18, 39, 18, 80, 7, 66, 28, 59, 32, 74, -17, 138, 40, 43, -63, 100, -6, 112, 27, 52, 12, 120, -36, 159, 55, 30, 43, 136, 12, 136, 3, 10, 54, 102 (list; graph; listen)
OFFSET

1,4

COMMENT

a(n)=Sigma[Phi[n]]-Phi[Sigma[n]] =A000203[A000010[n]]-A000010[A000203[n]].

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1000

EXAMPLE

n = 13: Sigma[13] = 14, Phi[14] = 6, Phi[13] = 12, Sigma[12] = 28, a(13) = 28-6 = 22.

PROGRAM

(PARI) { for (n=1, 1000, a=sigma(eulerphi(n)) - eulerphi(sigma(n)); write("b065395.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 18 2009]

CROSSREFS

A000203, A000010, A033632

Sequence in context: A152204 A114216 A086233 this_sequence A112411 A021970 A115335

Adjacent sequences: A065392 A065393 A065394 this_sequence A065396 A065397 A065398

KEYWORD

sign

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Nov 05 2001

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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