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A114063 Numbers n such that phi(n)=tau(n)^4, where tau(n)=A000005(n). 5
1, 17, 514, 8738, 32301, 33003, 36351, 41504, 42292, 43852, 51860, 62226, 549117, 561051, 571311, 599067, 617967, 629811, 634005, 657495, 673184, 674505, 683168, 701024, 705568, 718964, 722684, 732628, 745484, 759772, 774368 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For all large enough n, we have tau(n) < n^(1/5) and phi(n) > n^(4/5). Hence, tau(n)^4 < n^(4/5) < phi(n), implying that this sequence is finite. - Max Alekseyev, Mar 10 2016

LINKS

Enrique PĂ©rez Herrero, Table of n, a(n) for n=1..660

EXAMPLE

phi(33003)=20736. tau(33003)=12, 20736=12^4.

PROG

(PARI) isok(n) = eulerphi(n) == numdiv(n)^4; \\ Michel Marcus, Jan 22 2014

CROSSREFS

Cf. A020488, A062516, A063469, A063470, A112954, A112955, A175667, A068560, A068559.

Sequence in context: A012792 A012232 A031421 * A214135 A193120 A264858

Adjacent sequences:  A114060 A114061 A114062 * A114064 A114065 A114066

KEYWORD

fini,nonn

AUTHOR

Giovanni Resta, Feb 13 2006

STATUS

approved

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Last modified January 20 02:39 EST 2018. Contains 297939 sequences.