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A089437
Numbers k such that 4^k + 3 is prime.
6
1, 2, 3, 6, 8, 9, 14, 15, 42, 114, 195, 392, 555, 852, 1004, 1185, 2001, 2030, 2031, 2276, 8610, 8967, 10362, 11366, 15927, 16514, 17877, 19122, 19898, 27728, 29156, 61275, 102981, 117663, 181560, 239922, 342789, 371226, 717200, 937776, 970406, 1102722
OFFSET
1,2
COMMENTS
The halved even terms of A057732. - R. J. Mathar, Feb 26 2008
EXAMPLE
4^15 + 3 = 1073741827 a prime number.
PROG
(PARI) is(n)=ispseudoprime(4^n+3) \\ Charles R Greathouse IV, Feb 20 2017
CROSSREFS
Cf. A057732, A228026 (the actual primes).
Sequence in context: A111215 A099381 A289943 * A146768 A364958 A211370
KEYWORD
nonn,more
AUTHOR
Herman H. Rosenfeld (herm3(AT)pacbell.net), Dec 28 2003
EXTENSIONS
More terms from Ray Chandler, Dec 30 2003
More terms from R. J. Mathar, Feb 26 2008
a(33)-a(37) derived from A057732 by Robert Price, Apr 26 2014
a(38)-a(42) derived from A057732 by Amiram Eldar, Nov 16 2023
STATUS
approved