a(n) = Sum_{k=0..n} binomial(4*n+3*k+2,n-k).
A390474
a(n) = Sum_{k=0..n} binomial(4*n+3*k+2,n-k).
Terms
- a(0) =1a(1) =7a(2) =59a(3) =521a(4) =4694a(5) =42760a(6) =392235a(7) =3615130a(8) =33435645a(9) =310059105a(10) =2881274034a(11) =26819895379a(12) =249997116279
External references
- oeis: A390474