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A147570 a(n) = phi(A020492(n)). 1
1, 1, 2, 2, 4, 6, 8, 8, 24, 12, 24, 24, 24, 48, 48, 48, 72, 48, 120, 80, 72, 192, 180, 96, 144, 180, 240, 144, 192, 240, 336, 192, 288, 720, 480, 360, 720, 720, 480, 720, 720, 720, 672, 672, 576, 720, 960, 1440, 1872, 1680, 960, 1120, 1848, 2016, 1440, 1728, 1440 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

a(5) = phi(A020492(5)) = phi(12) = 4.

PROG

(MAGMA) [ a: n in [1..3500] | SumOfDivisors(n) mod a eq 0 where a is EulerPhi(n) ]; [From Klaus Brockhaus, Nov 09 2008]

(PARI) {for(n=1, 5000, a=eulerphi(n); if(sigma(n)%a==0, print1(a, ", ")))} [From Klaus Brockhaus, Nov 09 2008]

CROSSREFS

Cf. A000010 (Euler totient function phi(n)), A000203 (sigma(n), sum of divisors of n), A020492 (balanced numbers, numbers n such that phi(n) divides sigma(n)), A023897 (sigma(n) / phi(n) for balanced numbers), A147569.

Sequence in context: A194693 A176528 A108891 * A049625 A202102 A118303

Adjacent sequences:  A147567 A147568 A147569 * A147571 A147572 A147573

KEYWORD

easy,nonn

AUTHOR

Enoch Haga, Nov 07 2008

EXTENSIONS

Edited by Klaus Brockhaus, Nov 09 2008

STATUS

approved

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Last modified April 23 05:30 EDT 2014. Contains 240913 sequences.