a(n) = (Sum{1/C(i,j)})*LCM{C(i,j)}, 0 <= j <= i <= n.

Terms

a(0) =1a(1) =3a(2) =11a(3) =49a(4) =130a(5) =806a(6) =957a(7) =7723a(8) =17438a(9) =58154a(10) =63886a(11) =764858a(12) =826222a(13) =11530794a(14) =12314319a(15) =13092559a(16) =27732718a(17) =497636846a(18) =523706646a(19) =10443916834a(20) =10935791938a(21) =11426233362a(22) =11915393030a(23) =285278184586a(24) =296478322266