a(n) = 2*binomial(3*n-3, n-1)/(2*n-1) for n >= 2, and a(1) = 1.
A046646
a(n) = 2*binomial(3*n-3, n-1)/(2*n-1) for n >= 2, and a(1) = 1.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =24a(4) =110a(5) =546a(6) =2856a(7) =15504a(8) =86526a(9) =493350a(10) =2861430a(11) =16829280a(12) =100134216a(13) =601661144a(14) =3645533040a(15) =22249511328a(16) =136657509918a(17) =844061090670
External references
- oeis: A046646