a(n) = Sum_{k=0..floor(n/2)} binomial(5*n-2*k-1,n-2*k).
A371753
a(n) = Sum_{k=0..floor(n/2)} binomial(5*n-2*k-1,n-2*k).
Terms
- a(0) =1a(1) =4a(2) =37a(3) =376a(4) =4013a(5) =44064a(6) =492871a(7) =5585080a(8) =63901421a(9) =736575316a(10) =8540549322a(11) =99503540008
External references
- oeis: A371753