a(n) = n*(n+4)*(n+5)/6.

Terms

a(0) =0a(1) =5a(2) =14a(3) =28a(4) =48a(5) =75a(6) =110a(7) =154a(8) =208a(9) =273a(10) =350a(11) =440a(12) =544a(13) =663a(14) =798a(15) =950a(16) =1120a(17) =1309a(18) =1518a(19) =1748a(20) =2000a(21) =2275a(22) =2574a(23) =2898a(24) =3248a(25) =3625a(26) =4030a(27) =4464a(28) =4928a(29) =5423