OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
EXAMPLE
MATHEMATICA
f[n_]:=Plus@@Divisors[n]; lst={}; Do[p=Prime[n]; If[f[p-1]>2*p&&f[p+1]> 2*p, AppendTo[lst, p]], {n, 6!}]; lst
Select[Prime[Range[200]], DivisorSigma[1, #-1]>2#&&DivisorSigma[ 1, #+1]>2#&] (* Harvey P. Dale, Nov 10 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Aug 12 2009
EXTENSIONS
References to unrelated sequences removed by R. J. Mathar, Aug 21 2009
STATUS
approved