OFFSET

1,1

COMMENTS

Infinite under Dickson's conjecture. [Charles R Greathouse IV, Jul 24 2011]

LINKS

Andrea Raffetti, Table of n, a(n) for n = 1..999

EXAMPLE

5 is in the list because 5*6=30, 5*36=180 and both fall between a pair of twin primes (29,31 and 179,181).

MATHEMATICA

Select[Range[3100], And@@PrimeQ[{6#+1, 6#-1, 36#+1, 36#-1}]&] (* Harvey P. Dale, Jul 27 2011 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Andrea Raffetti, Jul 11 2011

STATUS

approved