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A135236 Numbers n such that n=s^phi(phi(s)) where s is sum of its digits. 3
1, 2, 3, 4, 6, 81, 234256, 614656, 1679616, 24794911296, 2518170116818978404827136, 4301431178848799040411011070519998467949638490834092425216 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Next term has 96 digits. In fact the sequence has only 14 terms, a(13)=250^40 and a(14)=370^48.

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

24794911296=(2+4+7+9+4+9+1+1+2+9+6)^phi(phi(2+4+7+9+4+9+1+1+2+9+6)) so 24794911296 is in the sequence.

CROSSREFS

Cf. A135234, A135235, A135237.

Sequence in context: A067244 A084811 A051856 * A029962 A259388 A049010

Adjacent sequences:  A135233 A135234 A135235 * A135237 A135238 A135239

KEYWORD

base,fini,nonn

AUTHOR

Farideh Firoozbakht, Nov 24 2007

STATUS

approved

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Last modified December 6 14:15 EST 2019. Contains 329806 sequences. (Running on oeis4.)