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 A159611 Indices, in the sequence of primes, of the known Fermat primes. 4
 2, 3, 7, 55, 6543 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A098006(a(n)) = 0. - Reinhard Zumkeller, Mar 26 2013 LINKS EXAMPLE 3, the Fermat prime corresponding to n = 0, is the 2nd prime, so a(0) = 2. 17, the Fermat prime corresponding to n = 2, is the 7th prime, so a(2) = 7. PROG (Haskell) import Data.List (elemIndices) a159611 n = a159611_list !! (n-1) a159611_list = map (+ 2) \$ elemIndices 0 a098006_list -- Reinhard Zumkeller, Mar 26 2013 (PARI) for(i=0, 10, isprime(f=2^2^i+1) & print1(primepi(f), ", ")) \\ Michel Marcus, Apr 28 2016 CROSSREFS Cf. A019434 (the Fermat primes), A000040 (the primes). Sequence in context: A270402 A253574 A238399 * A156585 A299923 A087358 Adjacent sequences:  A159608 A159609 A159610 * A159612 A159613 A159614 KEYWORD nonn,more AUTHOR Walter Nissen, Apr 16 2009 STATUS approved

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Last modified October 23 20:17 EDT 2019. Contains 328373 sequences. (Running on oeis4.)