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 A074002 #29 Dec 28 2024 09:44:06 %S A074002 0,0,6,6,30,72,252,756,2106,6642,19602,59292,176904,530712,1596510, %T A074002 4780782,14351094,43040160,129146724,387440172,1162202418 %N A074002 Number of elements of GF(3^n) with trace 0 and subtrace 2. %H A074002 Frank Ruskey, <a href="http://combos.org/TSGF3">Number of Elements of GF(3^n) with given trace and subtrace</a> %F A074002 A074000(n) + A074001(n) + a(n) = 3^(n-1) = A000244(n-1). - _R. J. Mathar_, Jun 14 2019 %o A074002 (Sage) %o A074002 def a(n): %o A074002 ans = 0 %o A074002 for x in GF(3^n): %o A074002 if x.charpoly().coefficients(sparse=False)[-3:-1]==[2, 0]: ans += 1 %o A074002 return ans # _Robin Visser_, Dec 28 2024 %Y A074002 Cf. A074000, A074001, A074003, A074004, A074005. %K A074002 nonn,more %O A074002 1,3 %A A074002 _Frank Ruskey_ and Nate Kube, Aug 19 2002 %E A074002 Formula and terms a(14)-a(15) 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, 43053282, 129146724, 387440172. - _Andrey Zabolotskiy_, Nov 08 2024 %E A074002 Terms a(17)-a(20) recomputed and added again (verified that the terms a(17), a(19), a(20) conjectured by Andrey Zabolotskiy are correct), and added term a(21). - _Robin Visser_, Dec 28 2024