Self-convolution of array T given by A026082.

Terms

a(0) =1a(1) =2a(2) =6a(3) =20a(4) =90a(5) =692a(6) =5774a(7) =48924a(8) =417440a(9) =3580036a(10) =30831756a(11) =266463804a(12) =2309848194a(13) =20074999500a(14) =174867895438