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 A143156 #15 Oct 09 2021 07:22:47 %S A143156 1,3,2,4,3,1,7,6,4,3,8,7,5,4,1,10,9,7,6,3,2,11,10,8,7,4,3,1,15,14,12, %T A143156 11,8,7,5,4,16,15,13,12,9,8,6,5,1,18,17,15,14,11,10,8,7,3,2,19,18,16, %U A143156 15,12,11,9,8,4,3,1,22,21,19,18,15,14,12,11,7,6,4,3 %N A143156 Triangle read by rows, T(n,k) = Sum_{j=k..n} A001511(j); = A000012 * (A001511 * 0^(n-k)) * A000012; 1<=k<=n. %C A143156 Row sums give A143157. %C A143156 Left border gives A005187. %C A143156 Right border gives A001511. %F A143156 Triangle read by rows, T(n,k) = Sum_{j=k..n} A001511(j); = A000012 * (A001511 * 0^(n-k)) * A000012; 1<=k<=n. %F A143156 From _Kevin Ryde_, Oct 07 2021: (Start) %F A143156 T(n,k) = A005187(n) - A005187(k-1). %F A143156 G.f.: (V(x) - V(x*y)) * y/((1-x)*(1-y)) where V(x) is the g.f. of A001511. %F A143156 (End) %e A143156 First few rows of the triangle = %e A143156 k=1 k=2 k=3 k=4 k=5 k=6 k=7 %e A143156 n=1: 1; %e A143156 n=2: 3, 2; %e A143156 n=3: 4, 3, 1; %e A143156 n=4: 7, 6, 4, 3; %e A143156 n=5: 8, 7, 5, 4, 1; %e A143156 n=6: 10, 9, 7, 6, 3, 2; %e A143156 n=7: 11, 10, 8, 7, 4, 3, 1; %e A143156 ... %e A143156 Row 6 = (10, 9, 7, 6, 3, 2) = partial sums of the first 6 terms of the ruler sequence, starting from the right: (1, 2, 1, 3, 1, 2,...). %o A143156 (PARI) T(n,k) = k--; 2*(n-k) - hammingweight(n) + hammingweight(k); \\ _Kevin Ryde_, Oct 07 2021 %Y A143156 Cf. A001511, A000012, A091512, A005187. %K A143156 nonn,easy,tabl %O A143156 1,2 %A A143156 _Gary W. Adamson_, Jul 27 2008