A053409 - OEIS

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A053409

Fibonacci numbers which are semiprimes.

21, 34, 55, 377, 4181, 17711, 121393, 1346269, 5702887, 165580141, 53316291173, 956722026041, 2504730781961, 308061521170129, 806515533049393, 14472334024676221, 1779979416004714189, 19740274219868223167, 573147844013817084101, 10284720757613717413913 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	FORMULA	`a(n) = A000045(A072381(n)).`
	EXAMPLE	`a(1)=21 because 21 is the product of two primes.`
	MATHEMATICA	`Select[Fibonacci@Range[120], Last/@FactorInteger[#]=={1, 1}&] (* From Vladimir Joseph Stephan Orlovsky, Jan 29 2012 *)`
	CROSSREFS	`Cf. A001358.` `Sequence in context: A135595 A082483 A075735 * A144205 A008946 A095738` `Adjacent sequences: A053406 A053407 A053408 * A053410 A053411 A053412`
	KEYWORD	`nonn`
	AUTHOR	`G. L. Honaker, Jr. (honak3r(AT)gmail.com), Jan 09 2000`

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Last modified February 15 05:29 EST 2012. Contains 205694 sequences.