a(n) = Sum_{k=0..n} 3^(n-k) * binomial(n-1,n-k) * binomial(2*k,k).
A360318
a(n) = Sum_{k=0..n} 3^(n-k) * binomial(n-1,n-k) * binomial(2*k,k).
Terms
- a(0) =1a(1) =2a(2) =12a(3) =74a(4) =466a(5) =2982a(6) =19320a(7) =126390a(8) =833220a(9) =5527190a(10) =36852052a(11) =246751854a(12) =1658106394a(13) =11176100138a(14) =75528743352a(15) =511600414554
External references
- oeis: A360318