Triangle read by rows: (1/3) * (A007318^2 - A007318^(-1)) as infinite lower triangular matrices.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =3a(5) =3a(6) =5a(7) =12a(8) =6a(9) =4a(10) =11a(11) =25a(12) =30a(13) =10a(14) =5a(15) =21a(16) =66a(17) =75a(18) =60a(19) =15a(20) =6a(21) =43a(22) =147a(23) =231a(24) =175a(25) =105a(26) =21a(27) =7a(28) =85a(29) =344