a(n) = [ Sum{(sqrt(j+1)-sqrt(i+1))^2} ], 1 <= i < j <= n.

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =6a(5) =10a(6) =16a(7) =25a(8) =35a(9) =48a(10) =65a(11) =84a(12) =108a(13) =135a(14) =166a(15) =203a(16) =244a(17) =290a(18) =342a(19) =400a(20) =464a(21) =535a(22) =613a(23) =698a(24) =790a(25) =890a(26) =999a(27) =1116a(28) =1242a(29) =1377