a(n) = (1/n)*Sum_{i=0..n-1} C(n,i)*C(n,i+1)*7^i*8^(n-i), a(0)=1.
A133308
a(n) = (1/n)*Sum_{i=0..n-1} C(n,i)*C(n,i+1)*7^i*8^(n-i), a(0)=1.
Terms
- a(0) =1a(1) =8a(2) =120a(3) =2248a(4) =47160a(5) =1059976a(6) =24958200a(7) =607693640a(8) =15175702200a(9) =386555020552
External references
- oeis: A133308