a(1)=0, a(2)=9; then distinct squares such that the sum of three successive terms is a square.

Terms

a(0) =0a(1) =9a(2) =16a(3) =144a(4) =36a(5) =1936a(6) =242064a(7) =11025a(8) =360000a(9) =19600a(10) =1089a(11) =106998336a(12) =1806336a(13) =9048064a(14) =9216a(15) =239121a(16) =23104a(17) =2250000a(18) =3240000a(19) =9025a(20) =2985984a(21) =1332542016a(22) =301401a(23) =2102405904a(24) =102252544a(25) =1289097216a(26) =19554084a(27) =7441984a(28) =1115136a(29) =4356