A086709 Primes p such that p-1 and p+1 are both divisible by fourth powers.

1249, 2753, 3727, 4049, 4801, 5023, 7937, 10529, 11503, 12799, 13121, 15391, 20897, 21871, 22193, 23167, 25759, 28351, 28751, 31249, 32561, 33857, 35153, 37423, 39041, 42929, 46817, 47791, 48751, 49409, 50383, 51679, 55889, 58481, 62047

Offset: 1

Author

Amarnath Murthy, Jason Earls, Jul 28 2003

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2000 from Vincenzo Librandi)

Crossrefs

Cf. A046101, A075432, A086708, A089212.

Programs

Mathematica

f[n_]:=Max[Last/@FactorInteger[n]]; lst={};Do[p=Prime[n];If[f[p-1]>=4&&f[p+1]>=4,AppendTo[lst,p]],{n,8!}];lst (* Vladimir Joseph Stephan Orlovsky, Oct 03 2009 *)
dfpQ[n_]:=Max[Transpose[FactorInteger[n]][[2]]]>3; Select[Prime[Range[ 6500]], dfpQ[#-1]&&dfpQ[#+1]&] (* Harvey P. Dale, May 11 2012 *)