a(n) = n*(n+13)*(n+14)/6.

Terms

a(0) =0a(1) =35a(2) =80a(3) =136a(4) =204a(5) =285a(6) =380a(7) =490a(8) =616a(9) =759a(10) =920a(11) =1100a(12) =1300a(13) =1521a(14) =1764a(15) =2030a(16) =2320a(17) =2635a(18) =2976a(19) =3344a(20) =3740a(21) =4165a(22) =4620a(23) =5106a(24) =5624a(25) =6175a(26) =6760a(27) =7380a(28) =8036a(29) =8729