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A216666 Smallest integer b such that (b+1)^p - b^p is prime for all primes p <= prime(n). 1
1, 1, 1, 1, 6524, 809652228, 30717523794, 55779743835 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

a(1)=a(2)=a(3)=a(4)=1 since 2^2-1, 2^3-1, 2^5-1 and 2^7-1 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

Jean-Louis Charton, Sep 13 2012

EXTENSIONS

a(7)=30717523794, Jean-Louis Charton, Sep 18 1012

a(8)=55779743835, Jean-Louis Charton, Oct 02 1012

STATUS

approved

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Last modified January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)