OFFSET
1,1
REFERENCES
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 165, p. 53, Ellipses, Paris 2008.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..2693 (terms < 10^12)
MATHEMATICA
qcp[n_, d_] := Block[{p, e}, {p, e} = Transpose@FactorInteger@n;
Length[p] > 1 && Max[e] == 1 && And @@ IntegerQ /@ ((n + d)/(p + d))]; Select[Range[10^6], qcp[#, 3] &] (* Giovanni Resta, May 21 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved