a(n) = Sum_{k=0..n} binomial(2*n,k) * binomial(3*n-k-1,n-k).
A370099
a(n) = Sum_{k=0..n} binomial(2*n,k) * binomial(3*n-k-1,n-k).
Terms
- a(0) =1a(1) =4a(2) =32a(3) =292a(4) =2816a(5) =28004a(6) =284000a(7) =2919620a(8) =30316544a(9) =317222212a(10) =3339504032a(11) =35329425124a(12) =375282559232
External references
- oeis: A370099