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A200823 Numbers k such that (2^k + k)*2^k + 1 is prime. 7
1, 3, 6, 14, 21, 27, 51, 61, 103, 123, 126, 414, 499, 1509, 2389, 5973, 8558, 12673 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The generalization of this sequence is possible with the primes of the form (b^n +- k)*b^n +- 1.
LINKS
Henri Lifchitz, New forms of primes
EXAMPLE
3 is in the sequence because (2^3 + 3)*2^3 + 1 = 89 is prime.
MATHEMATICA
lst={}; Do[If[PrimeQ[(2^n + n)*2^n+1], AppendTo[lst, n]], {n, 5000}]; lst
PROG
(PARI) is(n)=ispseudoprime((2^n+n)<<n+1) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Sequence in context: A109757 A075189 A291987 * A093866 A056596 A026341
KEYWORD
nonn,more
AUTHOR
Michel Lagneau, Nov 23 2011
EXTENSIONS
a(16)-a(18) from Michael S. Branicky, Jul 13 2023
STATUS
approved

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Last modified June 23 01:40 EDT 2024. Contains 373629 sequences. (Running on oeis4.)