

A144709


Values of n > 2 such that there is not a pair of primes (n^2+n+k, n^2+nk), 1 <= k < n, between successive squares n^2 and (n+1)^2.


0




OFFSET

1,1


COMMENTS

For n = 2,3,4, for example, we have prime pairs (5,7), (11,13), (17,23). Conjecture: the intervals (n^2,[n+1]^2) that do not contain at least one such pair are sparse as n gets large.


LINKS

Table of n, a(n) for n=1..8.
Twin primes


PROG

(PARI) isok(n) = {for (k=1, n1, if (isprime(n^2+n+k) && isprime(n^2+nk), return (0)); ); return (1); } \\ Michel Marcus, Aug 31 2013


CROSSREFS

Sequence in context: A108024 A095081 A243437 * A132239 A075432 A232882
Adjacent sequences: A144706 A144707 A144708 * A144710 A144711 A144712


KEYWORD

nonn,more


AUTHOR

Daniel Tisdale, Sep 19 2008


STATUS

approved



