login
A136352
Primorials P for which neither P-1 nor P+1 is prime.
5
510510, 9699690, 223092870, 6469693230, 7420738134810, 13082761331670030, 614889782588491410, 32589158477190044730, 1922760350154212639070, 117288381359406970983270, 7858321551080267055879090
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
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