Self-convolution of array T given by A027144.

Terms

a(0) =4a(1) =20a(2) =88a(3) =416a(4) =2464a(5) =12320a(6) =73344a(7) =373248a(8) =2286080a(9) =11768320a(10) =72968192a(11) =378533888a(12) =2368397312a(13) =12353986560a(14) =77788119040a(15) =407431675904