a(n) equals the coefficient of x^n in the (n-1)-th iteration of x*(1+x)/(1-x) for n>=1.
A185522
a(n) equals the coefficient of x^n in the (n-1)-th iteration of x*(1+x)/(1-x) for n>=1.
Terms
- a(0) =1a(1) =2a(2) =12a(3) =138a(4) =2320a(5) =51450a(6) =1418004a(7) =46736466a(8) =1793145792a(9) =78506270994
External references
- oeis: A185522