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 A252791 Numbers m such that 6^m + m is a semiprime. 1
 2, 3, 5, 7, 11, 23, 41, 55, 73, 91, 131, 199, 221, 287 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 2 is in this sequence because 6^2+2 = 2*19 is semiprime. 7 is in this sequence because 6^7+7 = 271*1033 and these two factors are prime. MATHEMATICA Select[Range[90], PrimeOmega[6^# + #]==2 &] PROG (MAGMA) IsSemiprime:=func; [m: m in [1..90] | IsSemiprime(s) where s is 6^m+m]; CROSSREFS Cf. similar sequences listed in A252788. Cf. A252659. Sequence in context: A288371 A158217 A030284 * A068148 A036344 A165802 Adjacent sequences:  A252788 A252789 A252790 * A252792 A252793 A252794 KEYWORD nonn,more AUTHOR Vincenzo Librandi, Dec 25 2014 EXTENSIONS a(10)-a(14) by Luke March, Jul 08 2015 STATUS approved

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Last modified September 26 16:43 EDT 2020. Contains 337374 sequences. (Running on oeis4.)