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A290329
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Iterate the map x -> A289667(x) starting at n; sequence gives primes reached, or -1 if no prime is ever reached.
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4
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2, 3, 71, 5, 71, 7, 71, 11, 23, 11, 5261, 13, 17, 23, 703455573449, 17, 703455573449, 19, 5261, 71, 703455573449, 23, 727, 17, 67, 21544131687786037881228990839860266551231, 79, 29, 21544131687786037881228990839860266551231, 31, 23, 239, 71, 229, 227, 37, 73
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OFFSET
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2,1
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COMMENTS
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LINKS
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MAPLE
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local nitr ;
nitr := n ;
while ( not isprime(nitr) and nitr <> 1) do
end do:
return nitr ;
end proc:
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MATHEMATICA
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Table[NestWhile[FromDigits[#, 3] &@ Flatten@ Map[IntegerDigits[#, 3] &, FactorInteger[#] /. {p_, e_} /; p > 0 :> If[e == 1, p, {p, e}]] &, n, ! PrimeQ@ # &], {n, 2, 38}] (* Michael De Vlieger, Jul 29 2017 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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