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 A074003 #23 Dec 28 2024 09:44:25 %S A074003 1,0,3,9,30,81,225,756,2187,6561,19602,59049,177633,530712,1594323, %T A074003 4782969,14351094,43046721,129127041,387440172,1162261467 %N A074003 Number of elements of GF(3^n) with trace 1 and subtrace 0. %C A074003 Same as the number of elements of GF(3^n) with trace 2 and subtrace 0. %H A074003 Frank Ruskey, <a href="http://combos.org/TSGF3">Number of Elements of GF(3^n) with given trace and subtrace</a> %o A074003 (Sage) %o A074003 def a(n): %o A074003 if n==1: return 1 %o A074003 ans = 0 %o A074003 for x in GF(3^n): %o A074003 if x.charpoly().coefficients(sparse=False)[-3:-1]==[0, 1]: ans += 1 %o A074003 return ans # _Robin Visser_, Dec 28 2024 %Y A074003 Cf. A074000, A074001, A074002, A074004, A074005. %K A074003 nonn,more %O A074003 1,3 %A A074003 _Frank Ruskey_ and Nate Kube, Aug 19 2002 %E A074003 Terms a(13)-a(16) corrected, unverified terms a(17)-a(20) removed. Based on the original Data in A074000-A074005, a(17)-a(20) are possibly equal to 14351094, 43046721, 129127041, 387440172. - _Andrey Zabolotskiy_, Nov 11 2024 %E A074003 Terms a(17)-a(20) recomputed and added again (verified that all the terms a(17)-a(20) conjectured by Andrey Zabolotskiy are correct), and added term a(21). - _Robin Visser_, Dec 28 2024