OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
MAPLE
MATHEMATICA
f[p_, e_] := (p^(e+1)-1)^2/(p-1)^2/(p^(2*e)-1); seqQ[1] = True; seqQ[n_] := IntegerQ [Times @@ (f @@@ FactorInteger[n])]; Select[Range[17160], seqQ] (* Amiram Eldar, Dec 11 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Yasutoshi Kohmoto, Sep 12 2006
STATUS
approved