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A123678
Numbers n such that Lucas(prime(prime(n))) is prime, where Lucas(k) = A000032(k).
3
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)).
FORMULA
a(n) = pi(A123677(n)).
a(n) = pi(pi(A277290(n))). - Bobby Jacobs, Oct 30 2016
CROSSREFS
Cf. A119984, A122534 (Numbers n such that Fibonacci(prime(prime(n))) is prime).
Sequence in context: A031015 A329581 A024639 * A208450 A037333 A183529
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