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 A070896 #13 Sep 08 2022 08:45:06
%S A070896 0,-1,-9,96,1250,-19440,-352947,7340032,172186884,-4500000000,
%T A070896 -129687123005,4086546038784,139788510734886,-5159146026151936,
%U A070896 -204350482177734375,8646911284551352320,389289535005334947848,-18580248257778920521728
%N A070896 Determinant of the Cayley addition table of Z_{n}.
%C A070896 a(n) is the determinant of the n X n matrix M_(i,j) = ((i+j) mod n) where i and j range from 0 to n-1. - _Benoit Cloitre_, Nov 29 2002
%C A070896 |a(n)| = number of labeled mappings from n points to themselves (endofunctions) with an even number of cycles. E.g.f.: (1/2)*LambertW(-x)^2/(1+LambertW(-x)). - _Vladeta Jovovic_, Mar 30 2006
%H A070896 G. C. Greubel, <a href="/A070896/b070896.txt">Table of n, a(n) for n = 1..385</a>
%F A070896 a(n) = (-1)^floor(n/2)*(1/2)*(n-1)*n^(n-1). - _Benoit Cloitre_, Nov 29 2002
%e A070896 a(3) = -9 because the determinant of {{0,1,2}, {1,2,0}, {2,0,1}} is -9.
%t A070896 Table[(-1)^Floor[n/2]*(1/2)*(n - 1)*n^(n - 1), {n, 1, 50}] (* _G. C. Greubel_, Nov 14 2017 *)
%o A070896 (PARI) a(n)=(-1)^floor(n/2)*(1/2)*(n-1)*n^(n-1)
%o A070896 (Magma) [(-1)^Floor(n/2)*(1/2)*(n-1)*n^(n-1): n in [1..50]]; // _G. C. Greubel_, Nov 14 2017
%Y A070896 Cf. A000312, A052182, A060281, A060435.
%K A070896 sign
%O A070896 1,3
%A A070896 _Santi Spadaro_, May 23 2002