

A180431


Numbers n such that 4*17^n+1 is prime.


1




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



