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A038524
Numbers k such that the k-th Fibonacci number is composite and the concatenation of its prime factors (written in base 10 in ascending order) is prime.
0
8, 24, 28, 34, 50, 52, 58, 71, 77, 163, 197, 235, 238, 319, 570, 669, 949, 958, 1211, 1305
OFFSET
1,1
EXAMPLE
F(24) = 46368 = 2^5 * 3^2 * 7 * 23 is composite and the concatenation 2222233723 is prime, so 24 is in the sequence.
CROSSREFS
KEYWORD
nonn,base,hard,more
AUTHOR
EXTENSIONS
More terms from Jens Kruse Andersen, Jan 05 2003
a(17)-a(18) from Ryan Propper, May 29 2006
a(19)-a(20) from Sean A. Irvine, Jan 16 2021
STATUS
approved