Sum of the next n nonnegative integers repeated (A004526).

Terms

a(0) =0a(1) =1a(2) =5a(3) =14a(4) =29a(5) =51a(6) =82a(7) =124a(8) =178a(9) =245a(10) =327a(11) =426a(12) =543a(13) =679a(14) =836a(15) =1016a(16) =1220a(17) =1449a(18) =1705a(19) =1990a(20) =2305a(21) =2651a(22) =3030a(23) =3444a(24) =3894a(25) =4381a(26) =4907a(27) =5474a(28) =6083a(29) =6735