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A168117 Primes whose indices are perfect numbers. 0
13, 107, 3541, 83243, 645072299, 215186133599, 3839719253921 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

a(n) = A000040(A000396(n)).

EXAMPLE

a(1)=13 because the first perfect number is 6 and the 6th prime is 13. a(2)=107 because the second perfect number is 28 and the 28th prime is 107.

CROSSREFS

Cf. A000040, A000396.

Sequence in context: A164301 A322499 A087305 * A244176 A038384 A038385

Adjacent sequences:  A168114 A168115 A168116 * A168118 A168119 A168120

KEYWORD

hard,more,nonn

AUTHOR

Omar E. Pol, Dec 09 2009

EXTENSIONS

More terms from Omar E. Pol and Max Alekseyev, Dec 10 2009

STATUS

approved

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Last modified October 17 21:37 EDT 2019. Contains 328134 sequences. (Running on oeis4.)