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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

Table of n, a(n) for n=1..4.

Generalized Fermat number at MathWorld

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

Sequence in context: A003395 A222607 A000411 * A202967 A230330 A252174

Adjacent sequences:  A180428 A180429 A180430 * A180432 A180433 A180434

KEYWORD

more,nonn

AUTHOR

Serge Batalov, Sep 04 2010

STATUS

approved

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Last modified June 1 20:49 EDT 2020. Contains 334765 sequences. (Running on oeis4.)