OFFSET
1,1
COMMENTS
This sequence also happens to be one of impossible prime factors of 2^(2^n)+7. To form the sequence one uses PARI {p(n) = (2^(2^n) + 7)/p} and the run the program up to only Eulerphi(Eulerphi(p)). - A.K. Devaraj, Dec 14 2009
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) ~ (4/3) n log n. - Charles R Greathouse IV, Aug 07 2012
MATHEMATICA
Select[Prime[Range[300]], MemberQ[{2, 3, 4}, Mod[#, 5]]&] (* Vincenzo Librandi, Aug 07 2012 *)
PROG
(Magma) [ p: p in PrimesUpTo(600) | p mod 5 in {2, 3, 4} ]; // Vincenzo Librandi, Aug 07 2012
(PARI) select(n->n%5>1, primes(50)) \\ Charles R Greathouse IV, Aug 07 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved