

A136352


Primorials P for which neither P1 nor P+1 is prime.


5



510510, 9699690, 223092870, 6469693230, 7420738134810, 13082761331670030, 614889782588491410, 32589158477190044730, 1922760350154212639070, 117288381359406970983270, 7858321551080267055879090
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OFFSET

1,1


COMMENTS

This sequence is different from A121069 and A002110.
For almost all primes p, p# is in this sequence by Brun's theorem.  Charles R Greathouse IV, Sep 14 2015


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..350


FORMULA

Compute P = product of the first k primes. If P is neither preceded nor followed by a prime add P to the sequence.


EXAMPLE

13# = 30030 is preceded by a prime but is not followed by a prime. 17# = 510510 is neither preceded nor followed by a prime.


CROSSREFS

Cf. A136349, A136350, A136351, A002110, A121069.
Sequence in context: A258362 A147574 A046325 * A138207 A249881 A205291
Adjacent sequences: A136349 A136350 A136351 * A136353 A136354 A136355


KEYWORD

easy,nonn


AUTHOR

Enoch Haga, Dec 25 2007


EXTENSIONS

Edited by and more terms from Charles R Greathouse IV, Sep 29 2008


STATUS

approved



