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A055698 Numbers n such that n | (sigma_4(n) + phi(n)^4). 0
1, 2, 6, 13588, 48238, 54490, 69004, 194460, 353228, 577980, 638652, 1478962, 1882188, 2190515, 2677740, 3404598, 3875508, 8456460, 9978863, 16320458, 41199780, 45112860, 76132715, 236405988, 357846865, 682983756, 689274612, 733141332, 1185444052, 1752193128 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sigma_4(n) is the sum of the 4th powers of the divisors of n (A001159).

LINKS

Table of n, a(n) for n=1..30.

MATHEMATICA

Do[If[Mod[DivisorSigma[4, n] + EulerPhi[n]^4, n]==0, Print[n]], {n, 1, 10^6}]

PROG

(PARI) isok(k) = (sigma(k, 4) + eulerphi(k)^4)%k == 0; \\ Jinyuan Wang, Mar 17 2020

CROSSREFS

Cf. A001159.

Sequence in context: A116899 A162146 A231545 * A121167 A115658 A337096

Adjacent sequences:  A055695 A055696 A055697 * A055699 A055700 A055701

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jun 09 2000

EXTENSIONS

More terms from Robert G. Wilson v, Mar 11 2013

More terms from Jinyuan Wang, Mar 17 2020

STATUS

approved

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Last modified May 27 03:13 EDT 2022. Contains 354093 sequences. (Running on oeis4.)