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%I #18 May 02 2022 01:38:28
%S 2,3,5,7,11,23,41,55,73,91,131,199,221,287
%N Numbers m such that 6^m + m is a semiprime.
%C From _Kevin P. Thompson_, May 01 2022: (Start)
%C a(15) >= 335.
%C 391, 443, 607, 683, 737, and 745 are also terms in this sequence. (End)
%H FactorDB, <a href="http://factordb.com/index.php?id=1100000000613180791">Status of 6^335+335</a>
%e 2 is in this sequence because 6^2+2 = 2*19 is semiprime.
%e 7 is in this sequence because 6^7+7 = 271*1033 and these two factors are prime.
%t Select[Range[90], PrimeOmega[6^# + #]==2 &]
%o (Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [m: m in [1..90] | IsSemiprime(s) where s is 6^m+m];
%Y Cf. similar sequences listed in A252788.
%Y Cf. A252659.
%K nonn,more
%O 1,1
%A _Vincenzo Librandi_, Dec 25 2014
%E a(10)-a(14) by _Luke March_, Jul 08 2015
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