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 A192511 #15 Jun 02 2024 08:23:48 %S A192511 0,0,18,112,1904,17184,229848,1686008,29713758 %N A192511 Number of conjugacy classes of primitive elements in GF(13^n) which have trace 0. %C A192511 Also number of primitive polynomials of degree n over GF(13) whose second-highest coefficient is 0. %F A192511 a(n) = A192216(n) / n. %o A192511 (GAP) %o A192511 p := 13; %o A192511 a := function(n) %o A192511 local q, k, cnt, x; %o A192511 q:=p^n; k:=GF(p, n); cnt:=0; %o A192511 for x in k do %o A192511 if Trace(k, GF(p), x)=0*Z(p) and Order(x)=q-1 then %o A192511 cnt := cnt+1; %o A192511 fi; %o A192511 od; %o A192511 return cnt/n; %o A192511 end; %o A192511 for n in [1..16] do Print (a(n), ", "); od; %o A192511 (Sage) # See A192507 (change first line p=3 to p=13) %Y A192511 Cf. A152049 (GF(2^n)), A192507 (GF(3^n)), A192508 (GF(5^n)), A192509 (GF(7^n)), A192510 (GF(11^n)). %K A192511 nonn,hard,more %O A192511 1,3 %A A192511 _Joerg Arndt_, Jul 03 2011 %E A192511 a(7)-a(9) from _Robin Visser_, Jun 01 2024