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A300010
Numbers k such that 3^k + k - 1 is a prime.
0
1, 3, 65, 123, 435, 465, 677, 947, 4215, 5615, 69749
OFFSET
1,2
COMMENTS
Corresponding primes: 3, 29, 10301051460877537453973547267907, 48519278097689642681155855396759336072749841943521979872949, ...
a(12), if it exists, is greater than 100000. - Michael S. Branicky, Oct 09 2024
MAPLE
select(k->isprime(3^k+k-1), [$1..1000]); # Muniru A Asiru, Apr 05 2018
MATHEMATICA
Flatten[{Select[Range[6000], PrimeQ[3^# + # - 1] &]}]
PROG
(Magma) [k: k in [1..700] | IsPrime(3^k+k-1)];
(PARI) lista(nn) = forstep(n=1, nn, 2, if(ispseudoprime(3^n + n - 1), print1(n, ", "))); \\ Altug Alkan, Apr 01 2018
CROSSREFS
Sequence in context: A275044 A205645 A326429 * A196798 A196586 A197043
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Apr 01 2018
EXTENSIONS
a(11) from Michael S. Branicky, Oct 08 2024
STATUS
approved