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 A383010 #8 Apr 12 2025 09:37:43
%S A383010 1,-2,30,-268,3130,-46470,823550,-16781368,387421227,-9999900090,
%T A383010 285311670622,-8916103453380,302875106592266,-11112006720144694,
%U A383010 437893890381622140,-18446744078004584688,827240261886336764194,-39346408075098212291754,1978419655660313589123998
%N A383010 a(n) = -Sum_{d|n} (-n)^d.
%o A383010 (PARI) a(n) = -sumdiv(n, d, (-n)^d);
%Y A383010 Cf. A066108, A383003.
%K A383010 sign,easy
%O A383010 1,2
%A A383010 _Seiichi Manyama_, Apr 12 2025