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 A143158 #20 Jan 14 2023 09:29:32 %S A143158 1,0,-1,-1,-2,-1,-1,-2,-1,0,-2,-3,-2,-1,-1,-1,-2,-1,0,0,1,-2,-3,-2,-1, %T A143158 -1,0,-1,-2,-3,-2,-1,-1,0,-1,0,-2,-3,-2,-1,-1,0,-1,0,0,-1,-2,-1,0,0,1, %U A143158 0,1,1,1,-2,-3,-2,-1,-1,0,-1,0,0,0,-1,-2,-3,-2,-1,-1,0,-1,0,0,0,-1,0,-3,-4,-3,-2,-2,-1,-2,-1,-1,-1,-2,-1,-1,-2,-3,-2,-1 %N A143158 Triangle read by rows, T(n,k) = Sum_{j=k..n} mu(j). %C A143158 Right border gives A008683. %C A143158 Left border gives A002321. %C A143158 Row sums give A068340. %H A143158 Reinhard Zumkeller, <a href="/A143158/b143158.txt">Rows n = 1..125 of triangle, flattened</a> %F A143158 Triangle read by rows, T(n,k) = Sum_{j=k..n} mu(j), where mu(n) = A008683. %F A143158 T(n, k) = A000012(n) * (A008683(n) * 0^(n-k)) * A000012(n). %e A143158 First few rows of the triangle = %e A143158 1; %e A143158 0, -1; %e A143158 -1, -2, -1; %e A143158 -1, -2, -1, 0; %e A143158 -2, -3, -2, -1, -1; %e A143158 -2, -3, -2, -1, -1, 0, -1; %e A143158 -2, -3, -2, -1, -1, 0, -1, 0; %e A143158 -1, -2, -1, 0, 0, 1, 0, 1, 1, 1; %e A143158 ... %e A143158 For example, T(5,3) = (-2) = Sum(-1, 0, -1), since mu(n) = 1, -1, -1, 0, -1, ... %t A143158 Table[Sum[MoebiusMu@ j, {j, k, n}], {n, 14}, {k, n}] // Flatten (* _Michael De Vlieger_, Dec 17 2015 *) %o A143158 (Haskell) %o A143158 import Data.List (tails) %o A143158 a143158 n k = a143158_tabl !! (n-1) !! (k-1) %o A143158 a143158_row n = a143158_tabl !! (n-1) %o A143158 a143158_tabl = map (map sum . init . tails) a054527_tabl %o A143158 -- _Reinhard Zumkeller_, Sep 04 2015 %o A143158 (PARI) T(n,k) = sum(j=k,n,moebius(j)) %Y A143158 Cf. A008683, A002321, A068340, A054527. %K A143158 tabl,sign,look %O A143158 1,5 %A A143158 _Gary W. Adamson_, Jul 27 2008 %E A143158 47th term = T(10,2) corrected by _Reinhard Zumkeller_, Sep 04 2015