A128547 Primes p such that p*q-p-q is prime where q=nextprime(p).

3, 5, 7, 13, 29, 37, 43, 71, 89, 107, 151, 163, 191, 199, 211, 239, 241, 277, 331, 401, 479, 569, 607, 643, 683, 719, 751, 773, 811, 823, 881, 907, 911, 937, 953, 1087, 1091, 1109, 1117, 1201, 1249, 1289, 1321, 1399, 1439, 1459, 1471, 1597, 1619, 1621, 1657

Offset: 1

Author

Zak Seidov, Mar 10 2007

Keywords

• nonn

Examples

			3*5-3-5=7 prime, 5*7-5-7=23 prime etc.
		

Links

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

Crossrefs

Cf. A096342, A126148, A128547.

Programs

Mathematica

Select[Table[Prime[n], {n, 400}], PrimeQ[#*NextPrime[#] - # - NextPrime[#]] &] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2012 *)
qnpQ[n_]:=Module[{q=NextPrime[n]},PrimeQ[n*q-n-q]]; Select[Prime[Range[ 500]],qnpQ] (* Harvey P. Dale, Feb 28 2015 *)