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A177030
Numbers k such that 11^k + 3^k - 1 is prime.
1
1, 7, 9, 33, 127, 153, 2327, 3607, 14803, 16431
OFFSET
1,2
COMMENTS
a(9) > 13518. - Daniel Starodubtsev, Apr 06 2020
FORMULA
A177027(n) = 11^a(n)+3^a(n)-1.
EXAMPLE
7 is in the sequence, because 11^7 + 3^7 - 1 = 19489357 is prime.
PROG
(Magma)[n: n in [0..1500]|IsPrime(11^n+3^n-1^n)]
(PARI) is(n)=ispseudoprime(11^n+3^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A272432 A272431 A261961 * A189974 A316184 A359367
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Dec 09 2010
EXTENSIONS
a(7)-a(8) from Daniel Starodubtsev, Apr 06 2020
a(9)-a(10) from Michael S. Branicky, Jul 15 2023
STATUS
approved