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 A118212 Numbers n such that the reversal of all five numbers n^1, n^2, n^3 n^4 and n^5 are primes. 4
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence is infinite because if n is in the sequence then for all natural numbers m, 10^m*n is in the sequence. Contribution from Farideh Firoozbakht, Sep 29 2009: (Start) 110218462 is the smallest term n such that the reversal of n^6 is also prime. A165698 is a subsequence of this sequence such that for each term n reversal(n^6) is also prime. (End) LINKS Table of n, a(n) for n=1..23. EXAMPLE 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. MATHEMATICA 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}] Select[Range[20000000], And@@PrimeQ[FromDigits[Reverse[ IntegerDigits[ #]]]&/@ (#^Range[5])]&] (* Harvey P. Dale, Jan 17 2014 *) CROSSREFS Cf. A118213. Cf. A165698. [From Farideh Firoozbakht, Sep 29 2009] Sequence in context: A361262 A185465 A254974 * A233750 A252014 A247725 Adjacent sequences: A118209 A118210 A118211 * A118213 A118214 A118215 KEYWORD base,easy,nonn AUTHOR Farideh Firoozbakht, Apr 21 2006 STATUS approved

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Last modified June 4 03:55 EDT 2023. Contains 363118 sequences. (Running on oeis4.)