%I #3 Mar 31 2012 12:38:28

%S 85,781,137257,28531167061

%N Semiprimes in A023037.

%C The terms a(5) etc. have at least 63 digits (if they exist), so the pattern of terms does not continue as in A001039. [From _R. J. Mathar_, Feb 27 2010]

%t f1[n_]:=Module[{s=0},Do[s+=n^a,{a,0,n-1}];s]; f2[n_]:=Last/@FactorInteger[n]=={1,1}||Last/@FactorInteger[n]=={2}; Select[Table[f1[n],{n,50}],f2[ # ]&]

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Feb 19 2010