Self-convolution square of A108447.

Terms

a(0) =1a(1) =2a(2) =9a(3) =48a(4) =282a(5) =1762a(6) =11488a(7) =77270a(8) =532239a(9) =3735488a(10) =26617976a(11) =192061278a(12) =1400453568a(13) =10303466638a(14) =76391703591a(15) =570195719792