a(n) = sigma(n*a(n-1)) for n>1 with a(1)=1.

A180709

a(n) = sigma(n*a(n-1)) for n>1 with a(1)=1.

Terms

    a(0) =1a(1) =3a(2) =13a(3) =98a(4) =1026a(5) =16940a(6) =318402a(7) =8751951a(8) =138772480a(9) =4323245864a(10) =120795955200

External references