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A038767 Numbers n for which n-th primorial + square of (n+1)-th prime is also a prime. 0
1, 2, 3, 4, 6, 13, 19, 28, 41, 66, 85 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

r = prime(n+1)^2 is the smallest possible composite number that, if added to the n-th 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

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Last modified August 23 00:23 EDT 2019. Contains 326211 sequences. (Running on oeis4.)