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A180431 Numbers n such that 4*17^n+1 is prime. 1
0, 6, 522, 178438 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
For n>0, members of the sequence may only be of form 4k+2 (otherwise the expression is divisible by 3 or 5). Therefore members of the sequence are a subset of A005574 and are Generalized Fermat primes.
LINKS
Eric Weisstein's World of Mathematics, Generalized Fermat Number.
EXAMPLE
For a(2) = 6 we have 4*17^6+1 = 96550277, which is prime.
MATHEMATICA
Do[ If[ PrimeQ[ 4*17^n+1], Print[ n ]], {n, 0, 10000}]
PROG
(PARI) is(n)=isprime(4*17^n+1) \\ Charles R Greathouse IV, May 15 2013
CROSSREFS
Cf. A005574.
Sequence in context: A003395 A222607 A000411 * A202967 A230330 A252174
KEYWORD
nonn,more
AUTHOR
Serge Batalov, Sep 04 2010
STATUS
approved

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Last modified May 28 12:54 EDT 2024. Contains 372913 sequences. (Running on oeis4.)