Shallow diagonal of triangular spiral in A051682.

Terms

a(0) =1a(1) =31a(2) =97a(3) =199a(4) =337a(5) =511a(6) =721a(7) =967a(8) =1249a(9) =1567a(10) =1921a(11) =2311a(12) =2737a(13) =3199a(14) =3697a(15) =4231a(16) =4801a(17) =5407a(18) =6049a(19) =6727a(20) =7441a(21) =8191a(22) =8977a(23) =9799a(24) =10657a(25) =11551a(26) =12481a(27) =13447a(28) =14449a(29) =15487