%I
%S 1,4,8,17,144,154,298
%N Numbers m such that 5^m + m is a semiprime.
%C a(8) > 413.  _Carl Schildkraut_, Aug 14 2015
%e 1 is in this sequence because 5^1+1 = 2*3 is semiprime.
%e 8 is in this sequence because 5^8+8 = 3*130211 and these two factors are prime.
%t Select[Range[413], PrimeOmega[5^# + #]==2 &]
%o (MAGMA) IsSemiprime:=func<i  &+[d[2]: d in Factorization(i)] eq 2>; [m: m in [1..110]  IsSemiprime(s) where s is 5^m+m];
%o (PARI) main(m)=select(m>bigomega(5^m + m)==2,vector(m,i,i)); \\ _Anders HellstrÃ¶m_, Aug 14 2015
%Y Cf. similar sequences listed in A252788.
%Y Cf. A252658.
%K nonn,more
%O 1,2
%A _Vincenzo Librandi_, Dec 24 2014
%E a(5)a(7) from _Carl Schildkraut_, Aug 14 2015
