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A074241
Numbers n such that phi(n+1) = reverse(phi(n)).
1
1, 3, 15, 129, 833, 5044, 59815, 267335, 297863, 9633693, 4642779313, 62935243460, 91770096041, 1648209018135
OFFSET
1,2
COMMENTS
a(15) > 2*10^12. - Giovanni Resta, Aug 12 2019
EXAMPLE
phi(129 + 1) = 48 = reverse(84) = reverse(phi(129)), so 129 is a term of the sequence.
MATHEMATICA
Select[Range[10^5], FromDigits[Reverse[IntegerDigits[EulerPhi[ # ]]]] == EulerPhi[ # + 1] &]
PROG
(PARI) isok(n) = eulerphi(n+1) == fromdigits(Vecrev(digits(eulerphi(n)))); \\ Michel Marcus, Aug 12 2019
CROSSREFS
Sequence in context: A330804 A335390 A075475 * A228365 A117694 A264795
KEYWORD
nonn,base,more
AUTHOR
Joseph L. Pe, Sep 18 2002
EXTENSIONS
a(8)-a(14) from Giovanni Resta, Aug 12 2019
STATUS
approved