This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A252793 #21 Sep 08 2022 08:46:10 %S A252793 1,3,5,7,11,15,21,25,75,107,221,257,273 %N A252793 Numbers m such that 8^m + m is a semiprime. %C A252793 Next terms: 347?, 479, 521, 551, .... - _Charles R Greathouse IV_, Aug 17 2015 %F A252793 1 is in this sequence because 8^1+1 = 3*3 is semiprime. %F A252793 7 is in this sequence because 8^7+7 = 3*699053 and these two factors are prime. %t A252793 Select[Range[70], PrimeOmega[8^# + #]==2 &] %o A252793 (Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [m: m in [1..70] | IsSemiprime(s) where s is 8^m+m]; %o A252793 (PARI) is(n)=bigomega(8^n+n)==2 \\ _Charles R Greathouse IV_, Aug 14 2015 %Y A252793 Cf. similar sequences listed in A252788. %Y A252793 Cf. A252661. %K A252793 nonn %O A252793 1,2 %A A252793 _Vincenzo Librandi_, Dec 25 2014 %E A252793 a(9)-a(10) from _Luke March_, Jul 26 2015 %E A252793 a(11) from _Carl Schildkraut_, Aug 14 2015 %E A252793 a(12)-a(13) from _Charles R Greathouse IV_, Aug 17 2015