A105453 Numbers k such that prime(k) + k*prime(k+1) is prime.

2, 14, 16, 20, 24, 30, 40, 44, 48, 72, 76, 84, 96, 120, 122, 160, 168, 182, 214, 230, 254, 266, 270, 280, 288, 292, 294, 330, 338, 360, 390, 428, 490, 496, 512, 540, 544, 546, 552, 560, 576, 578, 582, 644, 654, 656, 660, 714, 726, 740, 746, 750, 758, 762

Offset: 1

Author

Zak Seidov, May 02 2005

Keywords

• nonn
• changed

Programs

Mathematica

bb={}; Do[If[PrimeQ[Prime[n]+n*Prime[n+1]], bb=Append[bb, n]], {n, 2, 400, 2}]; bb
Select[Range[2, 1200], PrimeQ[Prime[#] + # Prime[# + 1]] &] (* Harvey P. Dale, May 02 2012 *)

PARI

is(n,p=prime(n))=isprime(p+nextprime(p+1)*n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

More terms from Harvey P. Dale, May 02 2012