Array for second (k=2) convolution of Chebyshev's S(n,x)=U(n,x/2) polynomials.

Terms

a(0) =1a(1) =3a(2) =6a(3) =-3a(4) =10a(5) =-12a(6) =15a(7) =-30a(8) =6a(9) =21a(10) =-60a(11) =30a(12) =28a(13) =-105a(14) =90a(15) =-10a(16) =36a(17) =-168a(18) =210a(19) =-60a(20) =45a(21) =-252a(22) =420a(23) =-210a(24) =15a(25) =55a(26) =-360a(27) =756a(28) =-560a(29) =105