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 A292781 #26 Oct 23 2018 19:17:29 %S A292781 1,-24,1,252,-24,-1472,252,1,4830,-1472,-24,-6048,4830,252,-16744, %T A292781 -6048,-1472,1,84480,-16744,4830,-24,-113643,84480,-6048,252,-115920, %U A292781 -113643,-16744,-1472,534612,-115920,84480,4830,1,-370944,534612,-113643,-6048,-24 %N A292781 Triangle read by rows: T(n,k) = T(n-k,k-1) with T(0,0) = 1 and T(n,0) = -1/n * Sum_{k=1..A003056(n)} (-1)^k * (2*k+1) * (n+1-A060544(k+1)) * T(n,k). %H A292781 Seiichi Manyama, <a href="/A292781/b292781.txt">Rows n = 0..481, flattened</a> %e A292781 First few rows are: %e A292781 1; %e A292781 -24, 1; %e A292781 252, -24; %e A292781 -1472, 252, 1; %e A292781 4830, -1472, -24; %e A292781 -6048, 4830, 252; %e A292781 -16744, -6048, -1472, 1; %e A292781 84480, -16744, 4830, -24; %e A292781 -113643, 84480, -6048, 252; %e A292781 -115920, -113643, -16744, -1472; %e A292781 534612, -115920, 84480, 4830, 1. %e A292781 ----------------------------------------- %e A292781 n=5 %e A292781 T(5,1) = T(4,0) = 4830, T(5,2) = T(3,1) = 252. %e A292781 T(5,0) = -1/5 * Sum_{k=1..2} (-1)^k * (2*k+1) * (5+1-A060544(k+1)) * T(n,k) = -1/5 * ((-3)*(-4)*4830 + 5*(-22)*252) = -6048. %e A292781 n=6 %e A292781 T(6,1) = T(5,0) = -6048, T(6,2) = T(4,1) = -1472, T(6,3) = T(3,2) = 1. %e A292781 T(6,0) = -1/6 * Sum_{k=1..3} (-1)^k * (2*k+1) * (6+1-A060544(k+1)) * T(n,k) = -1/6 * ((-3)*(-3)*(-6048) + 5*(-21)*(-1472) - 7*(-48)*1) = -16744. %o A292781 (Ruby) %o A292781 def A292781(n) %o A292781 ary = [[1]] %o A292781 (1..n).each{|i| %o A292781 m = ((Math.sqrt(1 + 8 * i) - 1) / 2).to_i %o A292781 a = (1..m).map{|j| ary[i - j][j - 1]} %o A292781 ary << [-(1..m).inject(0){|s, j| s + (-1) ** (j % 2) * (2 * j + 1) * (i - 9 * j * (j + 1) / 2) * a[j - 1]} / i] + a %o A292781 } %o A292781 ary.flatten %o A292781 end %o A292781 p A292781(20) %Y A292781 All columns are A000594. %Y A292781 Cf. A003056, A060544. %K A292781 sign,tabf %O A292781 0,2 %A A292781 _Seiichi Manyama_, Sep 23 2017