A217622 Prime(prime(2*n)).

5, 17, 41, 67, 109, 157, 191, 241, 283, 353, 401, 461, 547, 587, 617, 739, 797, 877, 967, 1031, 1087, 1171, 1217, 1409, 1447, 1499, 1597, 1669, 1741, 1823, 1913, 2063, 2099, 2269, 2351, 2417, 2549, 2647, 2719, 2803, 2909, 3019, 3109, 3229, 3299, 3407, 3517

Offset: 1

Author

Vincenzo Librandi, Oct 13 2012

Keywords

• nonn
• easy

Comments

Subsequence of A006450.

Using the Prime Number Theorem, prime(n) ~ n log n, the asymptotic behavior is A217622(n) ~ 2n (log 2n) log(2n log 2n) ~ 2n (log n)^2 ~ A230460(n). - M. F. Hasler, Oct 19 2013

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A006450, A066066, A031215, A230460.

Programs

Magma

[NthPrime(NthPrime(2*n)): n in [1..50] ]; //

Mathematica

Table[Prime[Prime[2n]], {n, 100}]

PARI

a(n)=prime(prime(2*n)) \\ Charles R Greathouse IV, Oct 20 2013

Formula

a(n) = A000040(A031215(n)). - Omar E. Pol, Oct 19 2013

a(n) = A006450(2n). - M. F. Hasler, Oct 20 2013