a(n) = Sum_{k=0..floor(n/3)} binomial(5*n-k+1,n-3*k).
A371776
a(n) = Sum_{k=0..floor(n/3)} binomial(5*n-k+1,n-3*k).
Terms
- a(0) =1a(1) =6a(2) =55a(3) =561a(4) =6005a(5) =66080a(6) =740342a(7) =8400074a(8) =96206994a(9) =1109874635a(10) =12877808194a(11) =150122945518
External references
- oeis: A371776