a(n) = (n-c_1)(n-c_2)...(n-c_k) where c_k is the k-th composite number and is also the largest composite number < n.

A080498

a(n) = (n-c_1)(n-c_2)...(n-c_k) where c_k is the k-th composite number and is also the largest composite number < n.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =3a(7) =8a(8) =15a(9) =48a(10) =210a(11) =1152a(12) =3780a(13) =19200a(14) =62370a(15) =322560a(16) =2162160a(17) =17418240a(18) =81081000a(19) =567705600a(20) =2481078600a(21) =16907304960a(22) =146659312800

External references