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 A124895 #11 May 12 2025 08:37:07
%S A124895 -1,-1,0,1,-1,0,-1,0,0,0,1,-1,1,-1,0,-1,0,0,0,-1,0,0,-1,1,1,1,1,0,1,0,
%T A124895 -1,0,-1,0,-1,0,1,1,0,-1,1,0,-1,1,0,-1,0,-1,0,0,0,-1,0,-1,0,1,0,-1,-1,
%U A124895 1,-1,-1,1,1,1,0,1,0,0,0,0,0,-1,0,0,0,1,0,-1,-1,1,1,1,1,1,-1,0,-1,-1,-1,0,-1,0,1,0,1,0,0,0,-1,0,-1,0,1,0,1,-1,0,-1,0,0,1,0,0,0,1,0,1,-1,0
%N A124895 Triangle read by rows, 1 <= k <= n: T(n,k) = mu(n^2 + k^2) with mu = A008683.
%F A124895 T(n,k) = A008683(A070216(n,k)).
%F A124895 T(n,1) = A124897(1); T(A049533(n),1) <> 0; T(A049532(n),1) = 0.
%F A124895 T(n,n) = -A000007(n-1).
%F A124895 A124896(n) = Sum_{k=1..n} abs(T(n,k)), row sums of absolute values.
%e A124895 Triangle begins:
%e A124895 -1
%e A124895 -1, 0
%e A124895 1, -1, 0
%e A124895 -1, 0, 0, 0
%e A124895 1, -1, 1, -1, 0
%e A124895 -1, 0, 0, 0, -1, 0
%e A124895 0, -1, 1, 1, 1, 1, 0
%e A124895 1, 0, -1, 0, -1, 0, -1, 0
%e A124895 1, 1, 0, -1, 1, 0, -1, 1, 0
%e A124895 -1, 0, -1, 0, 0, 0, -1, 0, -1, 0
%t A124895 row[n_] := Table[MoebiusMu[n^2 + k^2], {k, 1, n}]; Array[row, 15] // Flatten (* _Amiram Eldar_, May 12 2025 *)
%o A124895 (PARI) row(n) = vector(n, k, moebius(n^2 + k^2)); \\ _Amiram Eldar_, May 12 2025
%Y A124895 Cf. A000007, A008683, A049532, A049533, A070216, A124897.
%K A124895 sign,tabl,easy
%O A124895 1,1
%A A124895 _Reinhard Zumkeller_, Nov 12 2006