

A121534


LucasFibonacci prime twins: Prime Lucas numbers Lucas(k) such that Fibonacci numbers Fibonacci(k) are also prime.


6




OFFSET

1,1


COMMENTS

Indices for LucasFibonacci prime twins are A080327(n). Corresponding FibonacciLucas prime twins are A121533(n). Probable primes Fibonacci(148091) and Lucas(148091) are the next probable FibonacciLucas and LucasFibonacci prime twins. They have 30949 and 30950 digits.


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

a(1) = 7 because Lucas(4) = 7 is prime and Fibonacci(4) = 3 is prime too.


MATHEMATICA

Do[f=Fibonacci[n]; l=Fibonacci[n1]+Fibonacci[n+1]; If[PrimeQ[f]&&PrimeQ[l], Print[{f, l}]], {n, 10000}]
nn=1000; Transpose[Select[Thread[{Fibonacci[Range[nn]], LucasL[ Range[nn]]}], And@@PrimeQ[#]&]][[2]] (* Harvey P. Dale, Jul 08 2011 *)


CROSSREFS

Cf. A121533, A000045, A005478, A001605, A001606, A000032, A000204, A005479, A080327.
Sequence in context: A153867 A153325 A109907 * A083363 A027707 A046861
Adjacent sequences: A121531 A121532 A121533 * A121535 A121536 A121537


KEYWORD

nonn


AUTHOR

Alexander Adamchuk, Aug 05 2006


EXTENSIONS

a(1) and example corrected by Harvey P. Dale, Jul 08 2011


STATUS

approved



