a(n) = (1/24)*n*(n - 1)*(n - 3)*(n - 14).

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =-5a(5) =-15a(6) =-30a(7) =-49a(8) =-70a(9) =-90a(10) =-105a(11) =-110a(12) =-99a(13) =-65a(14) =0a(15) =105a(16) =260a(17) =476a(18) =765a(19) =1140a(20) =1615a(21) =2205a(22) =2926a(23) =3795a(24) =4830a(25) =6050a(26) =7475a(27) =9126a(28) =11025a(29) =13195