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Search: id:A118212
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| A118212 |
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Numbers n such that the reversal of all five numbers n^1, n^2, n^3 n^4 and n^5 are primes. |
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+0
2
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| 3244, 32440, 324400, 324886, 1109311, 1979137, 3244000, 3248860, 10212316, 10255493, 10282339, 10306511, 10503781, 10573126, 10657861, 10692107, 11093110, 11145841, 11171452, 19791370, 19855967, 19875058, 19912073
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This sequence is infinite because if n is in the sequence then for all natural numbers m, 10^m*n is in the sequence.
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EXAMPLE
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3244 is in the sequence because reversal(3244^k) for k=1,2,...,5
are respectively 4423, 63532501, 48705383143, 692349908447011,
and 422250654361652953 and these five numbers are primes.
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MATHEMATICA
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Do[If[PrimeQ[FromDigits[Reverse[IntegerDigits[n]]]] && PrimeQ[FromDigits[Reverse[IntegerDigits[n^2]]]] && PrimeQ [FromDigits[Reverse[IntegerDigits[n^3]]]] && PrimeQ[FromDigits [Reverse[IntegerDigits[n^4]]]] && PrimeQ[FromDigits[Reverse [IntegerDigits[n^5]]]], Print[n]], {n, 32000000}]
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CROSSREFS
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Cf. A118213.
Sequence in context: A048255 A091329 A020414 this_sequence A048421 A031645 A106722
Adjacent sequences: A118209 A118210 A118211 this_sequence A118213 A118214 A118215
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KEYWORD
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base,easy,nonn
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AUTHOR
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Farideh Firoozbakht (mymontain(AT)yahoo.com), Apr 21 2006
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