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A076515 Numbers n such that 1 + 3^n + 5^n is prime. 4
0, 12, 36, 48, 72, 120 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Next term, if it exists, is greater than 35000. - Vaclav Kotesovec, Jan 26 2016

No more terms up to 75000 (Previous range rechecked). All terms are multiples of 12: if n > 0 is not a multiple of 12, 1 + 3^n + 5^n is divisible by 3, 5 or 7. - Rick L. Shepherd, Aug 06 2017

LINKS

Table of n, a(n) for n=1..6.

MAPLE

A076515:=n->`if`(isprime(1+3^n+5^n), n, NULL): seq(A076515(n), n=0..200); # Wesley Ivan Hurt, Aug 06 2017

MATHEMATICA

Do[ If[ PrimeQ[1 + 3^n + 5^n], Print[n]], {n, 0, 3500, 2}]

Select[Range[0, 5000], PrimeQ[1+3^#+5^#]&] (* Harvey P. Dale, Mar 09 2012 *)

PROG

(MAGMA) [n: n in [0..1000]|IsPrime(3^n+5^n+1)] // Vincenzo Librandi, Jan 22 2011

(PARI) lista(nn) = for(n=0, nn, if(ispseudoprime(1 + 3^n + 5^n), print1(n, ", "))); \\ Altug Alkan, Jan 25 2016

CROSSREFS

Cf. A008594, A074507, A268064, A268065, A268067.

Sequence in context: A073543 A349020 A074234 * A039317 A298942 A322411

Adjacent sequences:  A076512 A076513 A076514 * A076516 A076517 A076518

KEYWORD

nonn,more

AUTHOR

Zak Seidov, Oct 17 2002

STATUS

approved

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Last modified August 13 18:03 EDT 2022. Contains 356107 sequences. (Running on oeis4.)