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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 (list; graph; refs; listen; history; text; internal format)
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: A004657 A054075 A062798 * A182828 A294229 A035256

Adjacent sequences:  A270814 A270815 A270816 * A270818 A270819 A270820

KEYWORD

nonn,more

AUTHOR

Altug Alkan, Mar 23 2016

STATUS

approved

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Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)