Principal diagonal of the convolution array A213573.

Terms

a(0) =1a(1) =17a(2) =93a(3) =349a(4) =1093a(5) =3093a(6) =8221a(7) =20957a(8) =51861a(9) =125509a(10) =298477a(11) =699789a(12) =1621285a(13) =3718325a(14) =8453181a(15) =19069885a(16) =42728245a(17) =95156901a(18) =210762253a(19) =464517485a(20) =1019214021a(21) =2227173397a(22) =4848613213a(23) =10519312029a(24) =22749902293a(25) =49056576773a(26) =105495131181a(27) =226291086157