

A229627


a(n) is the smallest prime m such that 2*m^k1 is prime for k = 1, 2, ..., n.


2




OFFSET

1,1


COMMENTS

The prime number 2 in the definition is used because 2 is the only prime p such that for more than one prime q, p*q^k 1 can be prime.


LINKS

Table of n, a(n) for n=1..7.


MATHEMATICA

a[1]=2; a[n_]:=a[n]=(For[m=PrimePi[a[n1]], Union[Table[PrimeQ[2 Prime[m]^k1], {k, n}]]!={True}, m++]; Prime[m])]


PROG

(PARI) a(n)=forprime(m=2, , for(k=1, n, if(!ispseudoprime(2*m^k1), next(2))); return(m)) \\ Charles R Greathouse IV, Oct 01 2013


CROSSREFS

Cf. A229626.
Sequence in context: A094877 A006560 A088251 * A140839 A320299 A292943
Adjacent sequences: A229624 A229625 A229626 * A229628 A229629 A229630


KEYWORD

nonn,more


AUTHOR

Farideh Firoozbakht, Sep 27 2013


EXTENSIONS

a(7) from Giovanni Resta, Oct 01 2013


STATUS

approved



