a(n) = floor(sqrt(2*n^5)).

Terms

a(0) =0a(1) =1a(2) =8a(3) =22a(4) =45a(5) =79a(6) =124a(7) =183a(8) =256a(9) =343a(10) =447a(11) =567a(12) =705a(13) =861a(14) =1037a(15) =1232a(16) =1448a(17) =1685a(18) =1944a(19) =2225a(20) =2529a(21) =2858a(22) =3210a(23) =3587a(24) =3990a(25) =4419a(26) =4874a(27) =5357a(28) =5866a(29) =6404