a(1)=1, a(n) = 2(n^(n-1)-1)/(n-1)^2.

A093462

a(1)=1, a(n) = 2(n^(n-1)-1)/(n-1)^2.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =14a(4) =78a(5) =622a(6) =6536a(7) =85598a(8) =1345210a(9) =24691358a(10) =518748492a(11) =12281130094a(12) =323584515590

External references