A086173 - OEIS

%I #16 Sep 08 2022 08:45:11

%S 2,8,12,14,18,30,54,66,72,80,90,94,102,110,124,144,150,160,178,184,

%T 186,198,208,210,222,224,234,250,260,264,266,280,312,336,342,370,390,

%U 400,414,432,450,462,468,470,472,476,510,564,570,596,598,600,616,652,690

%N Numbers k such that k*prime(k)-1 is prime.

%C See also A086172, A086174, A086175, A086176, A086177.

%H Vincenzo Librandi, <a href="/A086173/b086173.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[1000], PrimeQ[ # Prime[ # ]-1]&]

%o (Magma) [n: n in [1..800] | IsPrime(n*NthPrime(n) - 1)]; // _Vincenzo Librandi_, Oct 05 2012

%Y Cf. A086172, A086174, A086175, A086176, A086177.

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Jul 11 2003