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 A174559 #15 Mar 30 2012 18:52:05 %S A174559 -1,3,0,3,0,1,3,0,-2,0,3,0,-5,0,-1,3,0,-8,0,1,0,3,0,-11,0,6,0,1,3,0, %T A174559 -14,0,14,0,0,0,3,0,-17,0,25,0,-6,0,-1,3,0,-20,0,39,0,-20,0,-1,0,3,0, %U A174559 -23,0,56,0,-45,0,5,0,1 %N A174559 Triangle T(n,k)of the coefficients [x^(n-k)] of the polynomials q(0,x)=-1, q(1,x)=3*x, q(n,x)=x*q(n-1,x)-q(n-2,x) in row n,column k. A companion to A193002(n). %C A174559 a(n)= %C A174559 -1, :-1, %C A174559 3, 0, :3*x, %C A174559 3, 0, 1, :3*x^2+1, %C A174559 3, 0, -2, 0, :3*x^3-2*x, %C A174559 3, 0, -5, 0, -1, %C A174559 3, 0, -8, 0, 1, 0 %C A174559 3, 0, -11, 0, 6, 0, 1. %C A174559 Row sum=period 6:repeat -1, 3, 4, 1, -3, 4=-A117378(n)=A117378(n+3). %F A174559 a(n) + A193002(n)=4*A192174(n). %F A174559 a(n) - A193002(n)=2*A053119(n), Chebyshev's S(n,x). %Y A174559 Cf. A192011. %K A174559 sign,tabl %O A174559 0,2 %A A174559 _Paul Curtz_, Aug 20 2011