Principal diagonal of the convolution array A213753.

Terms

a(0) =1a(1) =16a(2) =111a(3) =576a(4) =2631a(5) =11292a(6) =46927a(7) =191680a(8) =775599a(9) =3122076a(10) =12531591a(11) =50220912a(12) =201088855a(13) =804798268a(14) =3220143903a(15) =12882607872a(16) =51534757599a(17) =206148206268a(18) =824612224663