A123678 Numbers n such that Lucas(prime(prime(n))) is prime, where Lucas(k) = A000032(k).

2, 3, 4, 5, 6, 20, 30, 117, 136, 1616, 5313

Offset

1,1

Comments

Indices of prime Lucas numbers are listed in A001606.

Numbers n such that Lucas(prime(n)) is prime are listed in A120561.

Primes in A120561 are listed in A123677(n) = prime(a(n)).

Links

Table of n, a(n) for n=1..11.

Formula

a(n) = pi(A123677(n)).

a(n) = pi(pi(A277290(n))). - Bobby Jacobs, Oct 30 2016

Crossrefs

Cf. A000032, A123677, A120561, A001606, A277290.

Cf. A119984, A122534 (Numbers n such that Fibonacci(prime(prime(n))) is prime).

Sequence in context: A031015 A329581 A024639 * A208450 A037333 A183529

Adjacent sequences: A123675 A123676 A123677 * A123679 A123680 A123681

Keyword

hard,more,nonn

Author

Alexander Adamchuk, Oct 05 2006

Extensions

5313 found by Henri Lifchitz, from Jens Kruse Andersen, Jul 24 2014

Status

approved