a(n) = Sum_{k=0..n} binomial(n+3*k+2,k).
A390471
a(n) = Sum_{k=0..n} binomial(n+3*k+2,k).
Terms
- a(0) =1a(1) =7a(2) =53a(3) =428a(4) =3591a(5) =30859a(6) =269507a(7) =2381233a(8) =21224067a(9) =190464262a(10) =1718577123a(11) =15576393434a(12) =141705054948
External references
- oeis: A390471