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A090875 a(n) is the smallest number m such that m^(2^k) + 2^(2^k) is prime for k=0,1,...,n. 2
1, 1, 1, 1, 1, 2321204055 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

The first five terms of this sequence correspond to Fermat primes.

According to the answers to Prime Puzzle 399 (see link), next term is larger than 2.3*10^12. - M. F. Hasler, Aug 02 2007

LINKS

Table of n, a(n) for n=0..5.

C. Rivera (ed.), Prime Puzzle # 399.

EXAMPLE

a(5)=2321204055 because 2321204055 is the smallest number m such that m^(2^k) + 2^(2^k) is prime for k=0,1,2,3,4 and 5.

CROSSREFS

Cf. A090872, A090873, A090874.

Sequence in context: A022240 A251490 A277720 * A132907 A038685 A017289

Adjacent sequences:  A090872 A090873 A090874 * A090876 A090877 A090878

KEYWORD

nonn

AUTHOR

Farideh Firoozbakht, Feb 06 2004

STATUS

approved

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Last modified December 12 07:31 EST 2019. Contains 329948 sequences. (Running on oeis4.)