Place where n-th 1 occurs in A023127.

Terms

a(0) =1a(1) =4a(2) =9a(3) =17a(4) =27a(5) =40a(6) =55a(7) =73a(8) =93a(9) =116a(10) =141a(11) =168a(12) =198a(13) =230a(14) =265a(15) =302a(16) =342a(17) =384a(18) =429a(19) =476a(20) =525a(21) =577a(22) =631a(23) =688a(24) =747a(25) =809a(26) =873a(27) =940a(28) =1009a(29) =1081