OFFSET
1,1
COMMENTS
This is the complement of A088176 in the set of odd primes. - R. J. Mathar, Jul 04 2013
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
a(n) ~ prime(n) ~ n log n. - Charles R Greathouse IV, Jun 28 2013
EXAMPLE
a(1) = 3 because 3 is prime and prevprime(3) - 2 = 2 - 2 = 0 is not prime,
a(2) = 5 because 5 is prime and prevprime(5) - 2 = 3 - 2 = 1 is not prime,
a(3) = 13 because 13 is prime and prevprime(13) - 2 = 11 - 2 = 9 is composite.
MATHEMATICA
Select[Prime[Range[2, 100]], Not[PrimeQ[NextPrime[#, -1] - 2]] &] (* Alonso del Arte, Jul 04 2013 *)
PROG
(PARI) is(n)=n>2 && !isprime(precprime(n-2)-2) && isprime(n) \\ Charles R Greathouse IV, Mar 18 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Irina Gerasimova, Jun 28 2013
STATUS
approved