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A033299 Smallest safe prime ((p-1)/2 is also prime) > n.

%I A033299 #9 Jul 08 2025 19:50:40
%S A033299 5,5,5,5,7,7,11,11,11,11,23,23,23,23,23,23,23,23,23,23,23,23,47,47,47,
%T A033299 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,59,59,
%U A033299 59,59,59,59,59,59,59,59,59,59,83,83,83,83,83,83,83,83,83
%N A033299 Smallest safe prime ((p-1)/2 is also prime) > n.
%H A033299 Michael S. Branicky, <a href="/A033299/b033299.txt">Table of n, a(n) for n = 1..10000</a>
%p A033299 with(numtheory); safeprime(n);
%o A033299 (Python)
%o A033299 from sympy import isprime, nextprime
%o A033299 def a(n):
%o A033299   p = nextprime(n)
%o A033299   while not isprime((p-1)//2): p = nextprime(p)
%o A033299   return p
%o A033299 print([a(n) for n in range(1, 68)]) # _Michael S. Branicky_, May 05 2021
%K A033299 nonn
%O A033299 1,1
%A A033299 _N. J. A. Sloane_
%E A033299 a(57) and beyond from _Michael S. Branicky_, May 05 2021