a(n) is the square of the coefficient of x^n in 1/(1 - x*A(x^2)), where g.f. A(x) = Sum_{n>=0} a(n)*x^n.
A121648
a(n) is the square of the coefficient of x^n in 1/(1 - x*A(x^2)), where g.f. A(x) = Sum_{n>=0} a(n)*x^n.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =4a(4) =9a(5) =25a(6) =64a(7) =256a(8) =729a(9) =2601a(10) =7921a(11) =28900a(12) =90000a(13) =318096a(14) =1016064a(15) =3888784a(16) =12694969a(17) =46881409a(18) =155825289a(19) =592435600a(20) =1987643889a(21) =7408217041a(22) =25153960000a(23) =95823678916a(24) =327811212304
External references
- oeis: A121648