a(1) = 1, a(n+1) is the smallest square greater than the n-th partial sum.

Terms

a(0) =1a(1) =4a(2) =9a(3) =16a(4) =36a(5) =81a(6) =169a(7) =324a(8) =676a(9) =1369a(10) =2704a(11) =5476a(12) =11025a(13) =21904a(14) =44100a(15) =88209a(16) =176400a(17) =352836a(18) =705600a(19) =1411344a(20) =2822400a(21) =5645376a(22) =11296321a(23) =22591009a(24) =45185284a(25) =90364036a(26) =180741136a(27) =361494169a(28) =722964544a(29) =1445976676