a(n) = (1/n)*Sum_{i=0..n-1} C(n,i)*C(n,i+1)*5^i*6^(n-i), a(0)=1.
A133306
a(n) = (1/n)*Sum_{i=0..n-1} C(n,i)*C(n,i+1)*5^i*6^(n-i), a(0)=1.
Terms
- a(0) =1a(1) =6a(2) =66a(3) =906a(4) =13926a(5) =229326a(6) =3956106a(7) =70572066a(8) =1291183806a(9) =24095736726a(10) =456879955026
External references
- oeis: A133306