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

1,1

Comments

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

Links

Table of n, a(n) for n=1..43.

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

Crossrefs

Cf. A086085, A086086

Sequence in context: A043075 A096673 A144960 * A071680 A141182 A127589

Adjacent sequences: A173823 A173824 A173825 * A173827 A173828 A173829

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Feb 25 2010

Status

approved