A134303 Least k such that k*2^n*(k*2^n-1)-1 is prime.

2, 1, 2, 1, 1, 3, 4, 2, 1, 1, 19, 15, 13, 9, 8, 4, 2, 1, 35, 29, 31, 26, 13, 12, 6, 3, 27, 25, 31, 20, 10, 5, 32, 16, 8, 4, 2, 1, 17, 9, 16, 8, 4, 2, 1, 5, 8, 4, 2, 1, 64, 32, 16, 8, 4, 2, 1, 29, 120, 60, 30, 15, 35, 41, 37, 60, 30, 15

Offset

1,1

Links

Pierre CAMI, Table of n, a(n) for n = 1..2500

Maple

A134303 := proc(n)
    for k from 1 do
        k*2^n*(k*2^n-1)-1 ;
        if isprime(%) then
            return k;
        end if;
    end do:
end proc:
seq(A134303(n), n=1..80) ; # R. J. Mathar, Nov 30 2011

Mathematica

lk[n_]:=Module[{k=1, n2=2^n}, While[!PrimeQ[k*n2(k n2-1)-1], k++]; k]; Array[ lk, 70] (* Harvey P. Dale, Sep 29 2017 *)

Crossrefs

Cf. A134304, A134305.

Sequence in context: A205810 A139368 A266506 * A078997 A024680 A083531

Adjacent sequences: A134300 A134301 A134302 * A134304 A134305 A134306

Keyword

nonn

Author

Pierre CAMI, Oct 19 2007

Status

approved