a(n) = least value such that sequence increases and pairwise differences are unique.

Terms

a(0) =1a(1) =5a(2) =6a(3) =8a(4) =14a(5) =24a(6) =35a(7) =49a(8) =61a(9) =81a(10) =103a(11) =120a(12) =153a(13) =181a(14) =219a(15) =243a(16) =288a(17) =324a(18) =398a(19) =449a(20) =489a(21) =576a(22) =639a(23) =704a(24) =792a(25) =900a(26) =952a(27) =983a(28) =1069a(29) =1211