Earliest sequence such that xy | a(x+y) for all x>=1, y>=1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =12a(4) =12a(5) =360a(6) =60a(7) =1680a(8) =2520a(9) =25200a(10) =2520a(11) =332640a(12) =27720a(13) =5045040a(14) =5405400a(15) =2882880a(16) =720720a(17) =220540320a(18) =12252240a(19) =4655851200a(20) =4888643760a(21) =5121436320a(22) =232792560a(23) =128501493120a(24) =26771144400a(25) =696049754400