

A216666


Smallest integer b such that (b+1)^p  b^p is prime for all primes p <= prime(n).


1




OFFSET

1,5


COMMENTS

a(1)=a(2)=a(3)=a(4)=1 since 2^21, 2^31, 2^51 and 2^71 are primes.
Open question: is this sequence infinite?


LINKS

Table of n, a(n) for n=1..8.


CROSSREFS

Cf. A216668.
Sequence in context: A156418 A258521 A068270 * A260979 A034627 A223217
Adjacent sequences: A216663 A216664 A216665 * A216667 A216668 A216669


KEYWORD

nonn,hard,more


AUTHOR

JeanLouis Charton, Sep 13 2012


EXTENSIONS

a(7)=30717523794, JeanLouis Charton, Sep 18 1012
a(8)=55779743835, JeanLouis Charton, Oct 02 1012


STATUS

approved



