a(0)=a(1)=a(2)=0; thereafter a(n) = n*a(n-1) + n*a(n-2)/(n-2) + (-1)^(n-1)*4/(n-2).
A186638
a(0)=a(1)=a(2)=0; thereafter a(n) = n*a(n-1) + n*a(n-2)/(n-2) + (-1)^(n-1)*4/(n-2).
Terms
- a(0) =0a(1) =0a(2) =0a(3) =4a(4) =14a(5) =78a(6) =488a(7) =3526a(8) =28858a(9) =264256a(10) =2678632a(11) =29787932a(12) =360669542a(13) =4723907966a(14) =66555492656
External references
- oeis: A186638