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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

Table of n, a(n) for n=1..5.

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 A087358 A255357

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 July 25 18:14 EDT 2017. Contains 289796 sequences.