A173828 Primes p such that p-+(floor(Sqrt(p)))^2 are primes.

7, 43, 47, 67, 149, 163, 167, 337, 353, 487, 587, 617, 787, 911, 947, 1367, 1777, 1783, 2333, 2347, 2503, 2927, 2953, 2963, 3023, 3607, 3613, 3637, 3643, 3697, 3709, 3847, 4363, 4397, 4423, 4463, 4483, 4903, 5273, 6113, 6143, 6197, 7103, 7187, 7193, 8117

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

f1[n_]:=n-(Floor[Sqrt[n]])^2; f2[n_]:=n+(Floor[Sqrt[n]])^2; lst={}; Do[p=Prime[n]; If[PrimeQ[f1[p]]&&PrimeQ[f2[p]], AppendTo[lst, p]], {n, 8!}]; lst
fQ[n_]:=Module[{c=Floor[Sqrt[n]]^2}, AllTrue[n+{c, -c}, PrimeQ]]; Select[ Prime[ Range[1200]], fQ] (* Harvey P. Dale, Dec 15 2021 *)

Crossrefs

Cf. A086085, A086086, A135932, A173826, A173827

Sequence in context: A229437 A043064 A175159 * A045800 A159254 A062336

Adjacent sequences: A173825 A173826 A173827 * A173829 A173830 A173831

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Feb 25 2010

Status

approved