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URL: https://oeis.org/A230028

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A230028
Numbers n such that phi(n) = reversal(n-20).
1
104, 824, 800024, 8000024, 84803024, 8483021444
OFFSET
1,1
COMMENTS
If p=10^m+3 is prime then 8*p is in the sequence.
84803024 is the only known term of the sequence which is not of this form.
a(7) > 10^11. - Giovanni Resta, Dec 13 2013
EXAMPLE
phi(104)=48=reversal(84)=reversal(104-20).
MATHEMATICA
Do[If[EulerPhi[n]==FromDigits[Reverse[IntegerDigits[n-20]]], Print[n]], {n, 21, 90000000}]
CROSSREFS
Sequence in context: A206014 A106298 A337145 * A340898 A132434 A187589
KEYWORD
nonn,base,bref,more
AUTHOR
Farideh Firoozbakht, Dec 13 2013
EXTENSIONS
a(6) from Giovanni Resta, Dec 13 2013
STATUS
approved