A086173 Numbers k such that k*prime(k)-1 is prime.

2, 8, 12, 14, 18, 30, 54, 66, 72, 80, 90, 94, 102, 110, 124, 144, 150, 160, 178, 184, 186, 198, 208, 210, 222, 224, 234, 250, 260, 264, 266, 280, 312, 336, 342, 370, 390, 400, 414, 432, 450, 462, 468, 470, 472, 476, 510, 564, 570, 596, 598, 600, 616, 652, 690

Offset: 1

Author

Zak Seidov, Jul 11 2003

Keywords

• easy
• nonn

Comments

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

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

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

Programs

Magma

[n: n in [1..800] | IsPrime(n*NthPrime(n) - 1)]; // Vincenzo Librandi, Oct 05 2012

Mathematica

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