a(n) is minimal such that a(n)+a(n-1) is a square and a(n) is not in {a(0), ..., a(n-1)}.

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =10a(5) =15a(6) =21a(7) =4a(8) =5a(9) =11a(10) =14a(11) =2a(12) =7a(13) =9a(14) =16a(15) =20a(16) =29a(17) =35a(18) =46a(19) =18a(20) =31a(21) =33a(22) =48a(23) =52a(24) =12a(25) =13a(26) =23a(27) =26a(28) =38a(29) =43