a(n) = 1*2*3*4*5*6*7 + 8*9*10*11*12*13*14 + 15*16*17*18*19*20*21 + ... + (up to n).

Terms

a(0) =1a(1) =2a(2) =6a(3) =24a(4) =120a(5) =720a(6) =5040a(7) =5048a(8) =5112a(9) =5760a(10) =12960a(11) =100080a(12) =1240560a(13) =17302320a(14) =17302335a(15) =17302560a(16) =17306400a(17) =17375760a(18) =18697680a(19) =45209520a(20) =603353520a(21) =603353542a(22) =603354026a(23) =603365664a(24) =603657120a(25) =611247120a(26) =816480720a(27) =6570915120a(28) =6570915149a(29) =6570915990