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 A143809 #6 Nov 20 2022 10:53:14 %S A143809 1,-1,1,-1,0,0,0,-1,0,-1,-1,0,0,0,-2,1,-1,0,0,0,-3,-1,0,0,0,0,0,-3,0, %T A143809 0,0,1,0,0,0,-4,0,0,0,0,0,0,0,0,-3,1,-1,0,0,2,0,0,0,0,-3,-1,0,0,0,0,0, %U A143809 0,0,0,0,-1,0,1,0,1,0,3,0,0,0,0,0,-2,-1,0,0,0,0,0,0,0,0,0,0,0,3,1,-1,0,0,0 %N A143809 Eigentriangle of the Mobius transform, (A054525). %C A143809 The eigentriangle of the Mobius transform may be defined by the operation consisting of the termwise product of A054525 row terms and the first n terms of A007554, where A007554: (1, 1, 0, -1, -2, -3, -3,...) = the eigensequence of A054525. %C A143809 This triangle has the following properties: %C A143809 Sum of n-th row terms = rightmost term of next row. %C A143809 Right border = A007554, the eigensequence of the Mobius transform. %C A143809 Row sums = A007554 shifted one place to the left: (1, 0, -1, -2, -3,...). %C A143809 Left border = mu(n), A008683. %C A143809 A054525 = the Mobius transform and A007554 = the eigensequence of A054525. %F A143809 Triangle read by rows, A054525 * (A007554 * 0^(n-k)); 1<=k<=n %e A143809 First few rows of the triangle: %e A143809 1; %e A143809 -1, 1; %e A143809 -1, 0, 0; %e A143809 0, -1, 0, -1; %e A143809 -1, 0, 0, 0, -2; %e A143809 1, -1, 0, 0, 0, -3; %e A143809 -1, 0, 0, 0, 0, 0, -3; %e A143809 0, 0, 0, 1, 0, 0, 0, -4; %e A143809 0, 0, 0, 0, 0, 0, 0, 0, -3; %e A143809 1, -1, 0, 0, 2, 0, 0, 0, 0, -3; %e A143809 ... %e A143809 Row 6 = (1, -1, 0, 0, 0, -3) = termwise product of row 6 of the Mobius transform (1, -1, -1, 0, 0, 1) and the first 6 terms of A007554, (the eigensequence of the Mobius transform): (1, 1, 0, -1, -2, -3). %Y A143809 Cf. A008683, A007554, A054525. %K A143809 tabl,sign %O A143809 1,15 %A A143809 _Gary W. Adamson_, Sep 01 2008