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 A208335 #13 Jan 22 2020 20:13:06 %S A208335 1,2,1,3,3,1,4,7,5,1,5,14,15,6,1,6,25,36,23,8,1,7,41,76,69,36,9,1,8, %T A208335 63,147,176,123,48,11,1,9,92,266,400,355,192,66,12,1,10,129,456,834, %U A208335 910,635,292,82,14,1,11,175,747,1626,2131,1833,1065,410,105,15,1 %N A208335 Triangle of coefficients of polynomials v(n,x) jointly generated with A208834; see the Formula section. %C A208335 row sums, u(n,1): A000129 %C A208335 row sums, v(n,1): A001333 %C A208335 alternating row sums, u(n,-1): 1,0,-1,-2,-3,-4,-5,-6,... %C A208335 alternating row sums, v(n,-1): 1,1,1,1,1,1,1,1,1,1,1,... %C A208335 Subtriangle of the triangle T(n,k) given by (1, 1, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - _Philippe Deléham_, Mar 26 2012 %F A208335 u(n,x) = u(n-1,x) + x*v(n-1,x), %F A208335 v(n,x) = (x+1)*u(n-1,x) + v(n-1,x), %F A208335 where u(1,x)=1, v(1,x)=1. %F A208335 From _Philippe Deléham_, Mar 26 2012: (Start) %F A208335 As DELTA-triangle T(n,k) with 0 <= k <= n: %F A208335 G.f.: (1-x+x^2-y^2*x^2)/(1-2*x+x^2-y*x^2-y^2*x^2). %F A208335 T(n,k) = 2*T(n-1,k) - T(n-2,k) + T(n-2,k-1) + T(n-2,k-2), T(0,0) = T(1,0) = T(2,1) = 1, T(2,0) = 2, T(1,1) = T(2,2) = 0. (End) %e A208335 First five rows: %e A208335 1; %e A208335 2, 1; %e A208335 3, 3, 1; %e A208335 4, 7, 5, 1; %e A208335 5, 14, 15, 6, 1; %e A208335 First five polynomials v(n,x): %e A208335 1 %e A208335 2 + x %e A208335 3 + 3x + x^2 %e A208335 4 + 7x + 5x^2 + x^3 %e A208335 5 + 14x + 15x^2 + 6x^3 + x^4 %e A208335 From _Philippe Deléham_, Mar 26 2012: (Start) %e A208335 (1, 1, -1, 1, 0, 0, 0, ...) DELTA (0, 1, 0, -1, 0, 0, ...) begins: %e A208335 1; %e A208335 1, 0; %e A208335 2, 1, 0; %e A208335 3, 3, 1, 0; %e A208335 4, 7, 5, 1, 0; %e A208335 5, 14, 15, 6, 1, 0; (End) %t A208335 u[1, x_] := 1; v[1, x_] := 1; z = 13; %t A208335 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208335 v[n_, x_] := (x + 1)*u[n - 1, x] + v[n - 1, x]; %t A208335 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208335 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208335 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208335 TableForm[cu] %t A208335 Flatten[%] (* A208334 *) %t A208335 Table[Expand[v[n, x]], {n, 1, z}] %t A208335 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208335 TableForm[cv] %t A208335 Flatten[%] (* A208335 *) %t A208335 Table[u[n, x] /. x -> 1, {n, 1, z}] (* u row sums *) %t A208335 Table[v[n, x] /. x -> 1, {n, 1, z}] (* v row sums *) %t A208335 Table[u[n, x] /. x -> -1, {n, 1, z}](* u alt. row sums *) %t A208335 Table[v[n, x] /. x -> -1, {n, 1, z}](* v alt. row sums *) %Y A208335 Cf. A208334. %K A208335 nonn,tabl %O A208335 1,2 %A A208335 _Clark Kimberling_, Feb 26 2012