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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 3 05:46 EDT 2020. Contains 336197 sequences. (Running on oeis4.)