A091179 A088878 indexed by A000040.

2, 3, 4, 5, 6, 9, 12, 14, 15, 16, 18, 19, 20, 27, 30, 31, 33, 38, 39, 42, 43, 44, 47, 54, 55, 56, 58, 59, 62, 63, 65, 67, 68, 69, 74, 79, 83, 84, 86, 89, 91, 93, 94, 99, 100, 102, 107, 108, 110, 122, 123, 129, 133, 134, 135, 139, 143, 147, 153, 154, 155, 156, 162, 167

Offset: 1

Author

Ray Chandler, Dec 27 2003

Keywords

• easy
• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A088878, A091180, A091181.

Programs

Maple

select(n -> isprime(3*ithprime(n)-2), [$1..1000]); # Robert Israel, Mar 04 2016

Mathematica

PrimePi@ Select[Prime@ Range@ 167, PrimeQ[3 # - 2] &] (* Michael De Vlieger, Mar 04 2016 *)

Formula

a(n)=k such that A000040(k) = A088878(n).

Extensions

Offset corrected by Michael De Vlieger, Mar 04 2016