(1,1) entry of powers of the orthogonal design shown below.

Terms

a(0) =1a(1) =-5a(2) =-17a(3) =1a(4) =121a(5) =235a(6) =-377a(7) =-2399a(8) =-2159a(9) =12475a(10) =40063a(11) =-7199a(12) =-294839a(13) =-539285a(14) =985303a(15) =5745601a(16) =4594081a(17) =-31031045a(18) =-94220657a(19) =28776001a(20) =717096601a(21) =1232761195a(22) =-2554153817a(23) =-13737635999a(24) =-9596195279a(25) =76971061435a(26) =221115489823a(27) =-96566450399