a(n) = A220371(n)/(4*A220371(n-1)).

Terms

a(0) =15a(1) =126a(2) =143a(3) =1020a(4) =399a(5) =1150a(6) =783a(7) =8184a(8) =1295a(9) =3198a(10) =1935a(11) =9212a(12) =2703a(13) =6270a(14) =3599a(15) =65520a(16) =4623a(17) =10366a(18) =5775a(19) =25596a(20) =7055a(21) =15486a(22) =8463a(23) =73720a(24) =9999a(25) =21630a(26) =11663a(27) =50172a(28) =13455a(29) =28798