a(1) =1; for n>=1: a(n) = product of numbers k <= sigma(n) such that k is not equal to sigma(d) for any divisor d of n where sigma = A000203.

A206033

a(1) =1; for n>=1: a(n) = product of numbers k <= sigma(n) such that k is not equal to sigma(d) for any divisor d of n where sigma = A000203.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =240a(4) =120a(5) =3326400a(6) =5040a(7) =4151347200a(8) =119750400a(10) =39916800a(12) =6227020800

External references