(1,3) entry of powers of the orthogonal design shown in A090592.

Terms

a(0) =1a(1) =2a(2) =-3a(3) =-20a(4) =-19a(5) =102a(6) =337a(7) =-40a(8) =-2439a(9) =-4598a(10) =7877a(11) =47940a(12) =40741a(13) =-254098a(14) =-793383a(15) =191920a(16) =5937521a(17) =10531602a(18) =-20499443a(19) =-114720100a(20) =-85944099a(21) =631152502a(22) =1863913697a(23) =-690240120a(24) =-14427876119a(25) =-24024071398a(26) =52946990037a(27) =274062479860a(28) =177496029461