OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Table[PrimePi[NextPrime[3Prime[n], -1]], {n, 60}] (* Harvey P. Dale, Feb 21 2014 *)
PROG
(PARI) a(n) = primepi(3*prime(n)) \\ Michel Marcus, Mar 22 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved