

A103959


Minimum prime p such that prime(n)*p  2 is prime.


2



2, 3, 3, 3, 3, 3, 5, 7, 3, 11, 13, 3, 11, 3, 3, 3, 5, 3, 3, 3, 7, 19, 11, 5, 7, 5, 3, 23, 7, 3, 3, 5, 3, 7, 5, 31, 7, 3, 3, 5, 17, 3, 3, 3, 5, 19, 3, 7, 29, 7, 5, 5, 61, 3, 3, 3, 11, 3, 3, 11, 7, 3, 3, 5, 3, 5, 3, 3, 3, 7, 11, 11, 19, 3, 61, 5, 29, 7, 3, 7, 17
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OFFSET

1,1


COMMENTS

Conjecture: a(n) <= prime(n). Tested to n=10000.


LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000


EXAMPLE

Prime(1)*22=2 is prime, so a(1)=2;
Prime(2)*32=7 is prime, so a(2)=3;


MATHEMATICA

Table[p=Prime[n]; k=1; pk=Prime[k]; cp=p*pk2; While[ !PrimeQ[cp], k=k+1; pk=Prime[k]; cp=p*pk2]; pk, {n, 100}]


CROSSREFS

Sequence in context: A055767 A029110 A249420 * A035375 A093493 A087162
Adjacent sequences: A103956 A103957 A103958 * A103960 A103961 A103962


KEYWORD

easy,nonn


AUTHOR

Lei Zhou, Feb 22 2005


STATUS

approved



