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A237418
Primes of the form 4^k + 15.
2
19, 31, 79, 271, 1039, 4111, 65551, 4194319, 67108879, 1073741839, 4294967311, 1099511627791, 4398046511119, 70368744177679, 4722366482869645213711, 75557863725914323419151
OFFSET
1,1
COMMENTS
Subsequence of A144487.
LINKS
FORMULA
a(n) = 4^A253773(n) + 15. - Elmo R. Oliveira, Nov 28 2023
EXAMPLE
65551 is a term because 4^8 + 15 = 65551 is prime.
MATHEMATICA
Select[Table[4^n + 15, {n, 1, 200}], PrimeQ]
PROG
(Magma) [a: n in [1..70] | IsPrime(a) where a is 4^n+15];
CROSSREFS
Cf. A000040, A144487, A253773 (corresponding k's).
Sequence in context: A106861 A107168 A243450 * A240126 A125602 A139847
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 22 2014
STATUS
approved