Dirichlet convolution of Catalan numbers with themselves.

Terms

a(0) =1a(1) =2a(2) =4a(3) =11a(4) =28a(5) =88a(6) =264a(7) =868a(8) =2864a(9) =9752a(10) =33592a(11) =117676a(12) =416024a(13) =1486064a(14) =5348936a(15) =19390573a(16) =70715340a(17) =259292608a(18) =955277400a(19) =3534536244a(20) =13128241368a(21) =48932567632a(22) =182965127280a(23) =686119347008