

A270817


Integers n such that (2^n  1) + (3^n  1) + (5^n  1) is a prime number.


0



1, 3, 4, 9, 11, 69, 117, 449, 675, 1119, 1959, 2687, 2859
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OFFSET

1,2


COMMENTS

Inspired by A268067.
Corresponding primes are 7, 157, 719, 1973317, 49007317, ...


LINKS

Table of n, a(n) for n=1..13.


EXAMPLE

4 is a term because (2^4  1) + (3^4  1) + (5^4  1) = 719 is a prime number.


MATHEMATICA

Select[Range@ 3000, PrimeQ[(2^#  1) + (3^#  1) + (5^#  1)] &] (* Michael De Vlieger, Mar 23 2016 *)


PROG

(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(3 + 2^n + 3^n + 5^n), print1(n, ", ")));


CROSSREFS

Cf. A268064, A268067.
Sequence in context: A054075 A062798 A327060 * A182828 A294229 A035256
Adjacent sequences: A270814 A270815 A270816 * A270818 A270819 A270820


KEYWORD

nonn,more


AUTHOR

Altug Alkan, Mar 23 2016


STATUS

approved



