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A290329 Iterate the map x -> A289667(x) starting at n; sequence gives primes reached, or -1 if no prime is ever reached. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Base 3 analog of A195264 and A230627.

LINKS

Chai Wah Wu, Table of n, a(n) for n = 2..47

MAPLE

A290329 := proc(n)

    local nitr ;

    nitr := n ;

    while ( not isprime(nitr) and nitr <> 1) do

        nitr := A289667(nitr) ;

    end do:

    return nitr ;

end proc:

seq(A290329(n), n=1..20) ; # R. J. Mathar, Aug 05 2017

MATHEMATICA

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 *)

CROSSREFS

Cf. A290328, A230627, A289667.

Sequence in context: A257173 A232618 A115892 * A145531 A140546 A234237

Adjacent sequences:  A290326 A290327 A290328 * A290330 A290331 A290332

KEYWORD

nonn,base

AUTHOR

Chai Wah Wu, Jul 27 2017

STATUS

approved

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Last modified September 17 11:47 EDT 2021. Contains 347477 sequences. (Running on oeis4.)