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%I #13 Sep 08 2022 08:46:10
%S 1,5,68,85,86,92,136
%N Numbers m such that 9^m + m is a semiprime.
%C a(8) > 435. - _Carl Schildkraut_, Aug 14 2015
%e 1 is in this sequence because 9^1+1 = 2*5 is semiprime.
%e 5 is in this sequence because 9^5+5 = 2*29527 and these two factors are prime.
%t Select[Range[435], PrimeOmega[9^# + #]==2 &]
%o (Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [m: m in [1..435] | IsSemiprime(s) where s is 9^m+m];
%Y Cf. similar sequences listed in A252788.
%Y Cf. A252662.
%K nonn,more
%O 1,2
%A _Vincenzo Librandi_, Dec 27 2014
%E a(4)-a(7) from _Carl Schildkraut_, Aug 14 2015