a(n) = self-convolution of row n of array T given by A027082.

Terms

a(0) =1a(1) =3a(2) =11a(3) =41a(4) =161a(5) =633a(6) =2457a(7) =9415a(8) =35663a(9) =133721a(10) =497025a(11) =1833499a(12) =6719707a(13) =24488183a(14) =88798775a(15) =320596441a(16) =1152996137a(17) =4132351481a(18) =14764629473a(19) =52606224267a(20) =186963146315a(21) =662947211163