A064361 - OEIS

%I #12 Jun 24 2018 18:32:25

%S 1,2,4,12,18,22,30,42,52,82,84,126,142,174,178,180,186,192,198,216,

%T 220,240,252,262,298,316,348,382,400,406,412,438,478,480,492,520,522,

%U 532,546,576,604,610,630,700,730,744,784,790,832,840,852,862,904,916,940

%N Numbers k such that prime(k)^2 + k is prime.

%H Harry J. Smith, <a href="/A064361/b064361.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[ Range[ 1000 ], PrimeQ[ Prime[ # ]^2 + # ] & ]

%o (PARI) j=[]; for(n=1,1500, if(isprime(prime(n)^2+n), j=concat(j,n))); j

%o (PARI) { n=0; for (m=1, 10^9, if (isprime(prime(m)^2 + m), write("b064361.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Sep 12 2009

%K easy,nonn

%O 1,2

%A _Jason Earls_, Sep 26 2001