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 A348183 #35 Jan 02 2024 16:13:00 %S A348183 1,0,-1,-2,0,250,5616,-33614,0,204073344,-900000000,-9431790764,0, %T A348183 10752962364222,-1870899108384768,-36328974609375000,0, %U A348183 22899384412078526344,-111400529859275793629184,-43843094862278417487512,0,2870507605405055660542502550,67015802375208384199755038720 %N A348183 a(n) is the determinant of the n X n matrix M = (m_{i,j}), i,j from 0 to n-1: m{i,j} = (i+j)^2 mod n. %C A348183 It seems that for values of n divisible by 4 -> a(n) = 0 and rank(M) = n/2. %e A348183 a(2) = |0^2 mod 2, 1^2 mod 2| = -1 %e A348183 |1^2 mod 2, 2^2 mod 2| %e A348183 -- %e A348183 |0^2 mod 3, 1^2 mod 3, 2^2 mod 3| %e A348183 a(3) = |1^2 mod 3, 2^2 mod 3, 3^2 mod 3| = -2 %e A348183 |2^2 mod 3, 3^2 mod 3, 4^2 mod 3| %t A348183 a[n_]:=Table[Mod[(i+j)^2,n],{i,0,n-1},{j,0,n-1}]; Join[{1},Table[Det[a[n]], {n, 22}]] (* _Stefano Spezia_, Oct 06 2021 *) %o A348183 (PARI) a(n) = matdet(matrix(n, n, i, j, i--; j--; (i+j)^2 % n)); \\ _Michel Marcus_, Oct 06 2021 %o A348183 (Python) %o A348183 from sympy import Matrix %o A348183 def A348183(n): return Matrix(n,n,[pow(i+j,2,n) for i in range(n) for j in range(n)]).det() # _Chai Wah Wu_, Nov 24 2021 %Y A348183 Cf. A070896. %K A348183 sign %O A348183 0,4 %A A348183 _Dennis Gruhlke_ and _Albert Böschow_, Oct 05 2021 %E A348183 a(14)-a(17) corrected by and more terms from _Stefano Spezia_, Oct 06 2021.