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A072395
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Numbers n such that reverse(phi(n)) = n.
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3
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1, 21, 63, 291, 2991, 6102, 46676013, 69460293, 2346534651, 6313047393, 23400000651, 80050617822
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| For all n, a(n) = reversal(A085331(n)), so see Comment on A085331. This sequence is a subsequence of A069215 and if m is a term of A069215 and 10 doesn't divide m then m is in this sequence. - Farideh Firoozbakht (mymontain(AT)yahoo.com), Jan 09 2005
a(13) > 10^11. - Donovan Johnson, Feb 03 2012
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EXAMPLE
| reverse(phi(6102)) = reverse(2016) = 6102, so 6102 is a term of the sequence.
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MATHEMATICA
| Select[Range[10^5], FromDigits[Reverse[IntegerDigits[EulerPhi[#]]]] == # &]
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CROSSREFS
| Cf. A085331, A069215, A102278.
Sequence in context: A113622 A069215 A115921 * A113781 A033481 A041862
Adjacent sequences: A072392 A072393 A072394 * A072396 A072397 A072398
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KEYWORD
| base,nonn,changed
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AUTHOR
| Joseph L. Pe (JosephL.Pe(AT)hotmail.com), Jul 21 2002
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 23 2002
More terms from Farideh Firoozbakht (mymontain(AT)yahoo.com), Jan 09 2005
Corrected Mathematica program [Harvey P. Dale, Oct 03 2011]
a(10)-a(12) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 03 2012
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