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 A071524 #22 Aug 20 2024 03:41:09
%S A071524 1,-1,-1,1,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,16,25,-25,-100,1,81,-16,-36,
%T A071524 0,1764,-3136,-196,324,16,-225,-1764,1521,9,-3969,-4356,4761,9,-1225,
%U A071524 -19881,5041,156816,-312481,-167281,219024,3600,-186624,-158404,5541316,3020644,-19554084,-1350244,198810000
%N A071524 Determinant of n X n matrix defined by m(i,j)=1 if i^2+j^2 is a prime, m(i,j)=0 otherwise.
%C A071524 Terms are also perfect squares.
%C A071524 Conjecture: a(n) = 0 for no n > 28. - _Zhi-Wei Sun_, Aug 26 2013
%C A071524 General conjecture: Let m be any nonnegative integer, and let a(m,n) be the n X n determinant with (i,j)-entry equal to 1 or 0 according as i^{2^m}+j^{2^m} is prime or not. Then a(m,n) is nonzero for large n. (It can be proved that (-1)^(n*(n-1)/2)*a(m,n) is always a square, see the comments in A228591.) - _Zhi-Wei Sun_, Aug 26-27 2013
%t A071524 a[n_]:=a[n]=Det[Table[If[PrimeQ[i^2+j^2]==True, 1, 0], {i, 1, n}, {j, 1, n}]]; Table[a[n], {n, 1, 30}] (* _Zhi-Wei Sun_, Aug 26 2013 *)
%t A071524 Table[Det[Table[If[PrimeQ[a^2+b^2],1,0],{a,n},{b,n}]],{n,60}] (* _Harvey P. Dale_, May 31 2019 *)
%o A071524 (PARI) for(n=1,60,print1(((matdet(matrix(n,n,i,j,isprime(i^2+j^2))))),","))
%Y A071524 Cf. A069191, A228591, A228552, A228557, A228559, A228561, A228574, A228578.
%K A071524 easy,sign
%O A071524 1,20
%A A071524 _Benoit Cloitre_, Jun 02 2002