|
%I #14 Sep 08 2022 08:45:00
%S 5,11,29,131,181,379,991,1721,2861,3539,6971,8009,10301,10711,17291,
%T 22349,26731,32941,36671,37441,39799,54521,58321,69431,79241,109891,
%U 122149,139501,161201,175979,186191,187921,202049,212981,214831,249499
%N Primes of the form p^2 + p - 1 when p is prime.
%C Previous name: Primes produced in A053184.
%H Vincenzo Librandi, <a href="/A053185/b053185.txt">Table of n, a(n) for n = 1..1200</a>
%t Select[#^2 + # - 1 &/@Prime[Range[200]], PrimeQ] (* _Vincenzo Librandi_, Aug 12 2017 *)
%o (PARI) isA053185(n)={local(r);r=0;for(i=floor(sqrt(n+1)),ceil(sqrt(n)-1),if(isprime(i) && n==i^2+i-1 && isprime(n),r=1));r} \\ _Michael B. Porter_, May 10 2010
%o (PARI) lista(nn) = forprime(p=2, nn, if (isprime(q=p^2+p-1), print1(q, ", "))); \\ _Michel Marcus_, Aug 12 2017
%o (Magma) [p: p in PrimesUpTo(600) | IsPrime(p) where p is p^2+p-1]; // _Vincenzo Librandi_, Aug 12 2017
%Y Cf. A053184.
%K easy,nonn
%O 1,1
%A _Enoch Haga_, Mar 01 2000
%E New name from _Michel Marcus_, Aug 12 2017
|
