A290328 -id:A290328 - cp's OEIS frontend

A290329 Iterate the map x -> A289667(x) starting at n; sequence gives primes reached, or -1 if no prime is ever reached.

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

Offset: 2

Chai Wah Wu, Jul 27 2017

Base 3 analog of A195264 and A230627.

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

Cf. A290328, A230627, A289667.

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

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 *)

A290350 Trajectory of 48 under the map x -> A289667(x).

Original entry on oeis.org

48, 201, 310, 1894, 5321, 12706, 19475, 38759, 16151, 23120, 16496, 49145, 108244, 499453, 3436777, 10278262, 33836945, 240512002, 913716328, 939389234, 3295603306, 27693125191, 43752137122, 225022142762, 2016929822398, 21026295155804, 66261353668847, 675731396348989

Offset: 1

Chai Wah Wu, Jul 28 2017

Chai Wah Wu, Table of n, a(n) for n = 1..121

Cf. A289667, A290328, A290329.

NestList[FromDigits[#, 3] &@ Flatten@ Map[IntegerDigits[#, 3] &, FactorInteger[#] /. {p_, e_} /; p > 0 :> If[e == 1, p, {p, e}]] &, 48, 27] (* Michael De Vlieger, Jul 29 2017 *)

cp's OEIS Frontend

A290329 Iterate the map x -> A289667(x) starting at n; sequence gives primes reached, or -1 if no prime is ever reached.

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Maple

Mathematica