OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
First term 11: 10={1,2,5,10},14={1,2,7,14} Second term 29: 28={1,2,4,7,14,28},32={1,2,4,8,16,32}
MATHEMATICA
f[n_]:=Length[Divisors[n]]; lst={}; Do[p=Prime[n]; If[PrimeQ[p+2]&&f[p-1]==f[p+3], AppendTo[lst, p]], {n, 7!}]; lst
Select[Range[11000], DivisorSigma[0, #-1]==DivisorSigma[0, #+3]&&AllTrue[{#, #+2}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 04 2019 *)
PROG
(PARI) forprime(p=o=0, 1e4, (2+o==o=p)&&numdiv(p-3)==numdiv(p+1)&&print1(p-2", ")) \\ M. F. Hasler, Jul 31 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Dec 14 2009
EXTENSIONS
Name edited by M. F. Hasler, Jul 31 2015
STATUS
approved