

A038767


Numbers n for which nth primorial + square of (n+1)th prime is also a prime.


0



1, 2, 3, 4, 6, 13, 19, 28, 41, 66, 85
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OFFSET

1,2


COMMENTS

r = prime(n+1)^2 is the smallest possible composite number that, if added to the nth primorial, might give a prime.


LINKS

Table of n, a(n) for n=1..11.


FORMULA

a(n) = A002110(n) + prime(n+1)^2 is prime; n so that A054758(n)=1.


EXAMPLE

a(5)=6, 6th primorial is 30030, square of 7th prime is 289, sum gives 30319, a prime. No more were found below 200.


CROSSREFS

A002110, A054758.
Sequence in context: A096988 A066463 A073146 * A188715 A174046 A095991
Adjacent sequences: A038764 A038765 A038766 * A038768 A038769 A038770


KEYWORD

nonn


AUTHOR

Labos Elemer, May 04 2000


STATUS

approved



