a(n) = (1/(5*n+4)) * Sum_{k=0..n} (5*k+4) * binomial(5*n+4,n-k).
A390780
a(n) = (1/(5*n+4)) * Sum_{k=0..n} (5*k+4) * binomial(5*n+4,n-k).
Terms
- a(0) =1a(1) =5a(2) =36a(3) =300a(4) =2711a(5) =25806a(6) =254746a(7) =2583408a(8) =26748921a(9) =281581835a(10) =3004427056a(11) =32418260592a(12) =353128699929
External references
- oeis: A390780