OFFSET
1,1
COMMENTS
Numbers of the form n=p^2*q^3 where p and q are two different primes and where n+1 and n-1 are both in A005117.
MATHEMATICA
f[n_]:=Last/@FactorInteger[n]=={2, 3}||Last/@FactorInteger[n]=={3, 2}; << NumberTheory`NumberTheoryFunctions` lst={}; Do[If[f[n], If[SquareFreeQ[n-1]&&SquareFreeQ[n+1], AppendTo[lst, n]]], {n, 3*9!}]; lst
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Oct 26 2009
EXTENSIONS
Definition narrowed by R. J. Mathar, Oct 28 2009
STATUS
approved