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Search: id:A108777
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| A108777 |
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Numbers n such that a^t + b^t + c^t + ... is prime, where a*b*c* ... is the prime factorization of n with multiplicity and t is the reversal of n. |
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1
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OFFSET
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1,1
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EXAMPLE
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a(3)=75 because 75=3*5^2 and 75 reversed is 57 and 3^57 + 5^57 + 5^57 = 13877787807816026798194477932746894440813, a prime.
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MATHEMATICA
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fQ[n_] := PrimeQ[Plus @@ (Flatten[ Table[ #[[1]], {#[[2]]}] & /@ FactorInteger[n]]^FromDigits[ Reverse[ IntegerDigits[ n]] ])]; Do[ If[ fQ[n], Print[n]], {n, 2200}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 28 2005)
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CROSSREFS
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Cf. A082813.
Sequence in context: A055233 A104045 A102546 this_sequence A000132 A060317 A033583
Adjacent sequences: A108774 A108775 A108776 this_sequence A108778 A108779 A108780
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KEYWORD
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base,more,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Jun 27 2005
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EXTENSIONS
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300, 500, 640 from Robert G. Wilson v, Jun 27 2005
4100 and 8300 from Hans Havermann, Jun 29 2005
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