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 A074000 #29 Dec 30 2024 16:55:42 %S A074000 1,1,3,9,21,99,225,729,2187,6561,19845,58563,177633,531441,1594323, %T A074000 4782969,14344533,43059843,129127041,387420489,1162261467 %N A074000 Number of elements of GF(3^n) with trace 0 and subtrace 0. %H A074000 Frank Ruskey, <a href="http://combos.org/TSGF3">Number of Elements of GF(3^n) with given trace and subtrace</a> %F A074000 Appears to satisfy a linear recurrence of order 5 with signature (0, 3, 9, 18, 27). This also applies to sequences A074001-A074005. - _Andrey Zabolotskiy_, Dec 30 2024 %o A074000 (Sage) %o A074000 def a(n): %o A074000 if n==1: return 1 %o A074000 ans = 0 %o A074000 for x in GF(3^n): %o A074000 if x.charpoly().coefficients(sparse=False)[-3:-1]==[0, 0]: ans += 1 %o A074000 return ans # _Robin Visser_, Dec 28 2024 %Y A074000 Cf. A074001, A074002, A074003, A074004, A074005. %Y A074000 Cf. A073947, A053548. %K A074000 nonn,more %O A074000 1,3 %A A074000 _Frank Ruskey_ and Nate Kube, Aug 19 2002 %E A074000 a(18) corrected and a(21) added by _Robin Visser_, Dec 28 2024