A173826 Primes p such that p-+floor(Sqrt(p)) are primes.

5, 37, 47, 151, 331, 349, 593, 617, 907, 911, 937, 941, 1789, 1831, 2341, 2389, 2399, 2957, 3617, 3631, 3673, 3719, 4457, 5261, 5309, 6121, 6151, 6199, 6221, 7103, 7127, 7213, 8101, 8179, 9323, 9337, 9377, 10529, 10589, 11789, 13007, 13033, 13037

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Feb 25 2010

Keywords

• nonn

Comments

5-+2->primes, 37-+6->primes,..

Crossrefs

Cf. A086085, A086086

Programs

Mathematica

f1[n_]:=n-Floor[Sqrt[n]];f2[n_]:=n+Floor[Sqrt[n]];lst={};Do[p=Prime[n];If[PrimeQ[f1[p]]&&PrimeQ[f2[p]],AppendTo[lst,p]],{n,8!}];lst