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 A086147 #8 Jul 08 2018 19:59:47
%S A086147 1,13,219,367,4891,1977,36085,9791,46731,39133,479157,37119,1289911,
%T A086147 243703,375219,305599,6991319,299913,11500123,667219,2610657,3723423,
%U A086147 40035651,781127,14928331,8544673,11297307,4540153,129539703,2739477,209881105,9748415
%N A086147 Sum of the orders of the elements in the group GL(2,Z_n).
%H A086147 Eric M. Schmidt, <a href="/A086147/b086147.txt">Table of n, a(n) for n = 1..60</a>
%F A086147 a(n) = Sum_{k=1..n} k*A316566(n, k). - _Andrew Howroyd_, Jul 07 2018
%o A086147 (GAP) A086147 := n -> Sum(ConjugacyClasses(GL(2,ZmodnZ(n))), cc->Size(cc) * Order(Representative(cc))); # _Eric M. Schmidt_, May 18 2013
%Y A086147 Cf. A000252, A036391, A316566.
%K A086147 nonn
%O A086147 1,2
%A A086147 Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 25 2003
%E A086147 Corrected and extended by _Eric M. Schmidt_, May 18 2013