A165353 - OEIS

%I #12 Sep 08 2022 08:45:47

%S 7,17,23,31,41,71,73,79,103,113,127,151,191,233,257,281,311,337,367,

%T 383,409,433,463,487,569,577,593,601,607,647,809,887,911,953,977,1039,

%U 1049,1087,1097,1153,1193,1201,1223,1279,1297,1321,1361,1399,1433,1481,1487

%N Primes p such that p+(p^2-1)/8 is a prime number.

%H Vincenzo Librandi, <a href="/A165353/b165353.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n)+(a(n)^2-1)/8 = A165352(n).

%t Select[Prime[Range[250]], PrimeQ[# + (#^2 - 1)/8] &] (* _Vincenzo Librandi_, Sep 01 2012 *)

%o (Magma) [n: n in [3..1500] |IsPrime(n) and IsPrime(n+(n^2-1) div 8)]; // _Vincenzo Librandi_, Sep 01 2012

%Y Cf. A165352, A165354.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Sep 16 2009

%E More terms from _R. J. Mathar_, Sep 21 2009