Principal diagonal of the convolution array A213582.

Terms

a(0) =1a(1) =9a(2) =38a(3) =120a(4) =327a(5) =819a(6) =1948a(7) =4482a(8) =10085a(9) =22341a(10) =48930a(11) =106236a(12) =229075a(13) =491175a(14) =1048184a(15) =2227782a(16) =4718097a(17) =9960921a(18) =20970910a(19) =44039520a(20) =92273951a(21) =192937179a(22) =402652308a(23) =838859850a(24) =1744829437a(25) =3623877549a(26) =7516191578a(27) =15569255172a(28) =32212253355a(29) =66571991631