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A215434
Primes of form 2^k + k^2 - 1.
14
2, 7, 31, 1123, 1180591620717411308323, 21778071482940061661655974875633165551139, 89202980794122492566142873090593446023942979, 1569275433846670190958947355801916604025588861116008664323
OFFSET
1,1
LINKS
MATHEMATICA
Select[Table[2^n + n^2 - 1, {n, 0, 300}], PrimeQ]
PROG
(Magma) [a: n in [0..250] | IsPrime(a) where a is 2^n+n^2-1];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 03 2012
STATUS
approved