a(n) = 2*(n-1)*( a(n-1)+a(n-2) ) starting a(1)=a(2)=1.
A142703
a(n) = 2*(n-1)*( a(n-1)+a(n-2) ) starting a(1)=a(2)=1.
Terms
- a(0) =1a(1) =1a(2) =8a(3) =54a(4) =496a(5) =5500a(6) =71952a(7) =1084328a(8) =18500480a(9) =352526544a(10) =7420540480a(11) =171007474528
External references
- oeis: A142703