a(n) = Sum_{k=0..n} 2^(n-k) * binomial(5*n,k).
A386699
a(n) = Sum_{k=0..n} 2^(n-k) * binomial(5*n,k).
Terms
- a(0) =1a(1) =7a(2) =69a(3) =733a(4) =8061a(5) =90462a(6) =1028871a(7) =11814376a(8) =136643085a(9) =1589311381a(10) =18569375114a(11) =217773347502
External references
- oeis: A386699