a(n) = 2^n*Sum_{k=0..n} (n+k)!/((n-k)!*k!*4^k).
A043301
a(n) = 2^n*Sum_{k=0..n} (n+k)!/((n-k)!*k!*4^k).
Terms
- a(0) =1a(1) =3a(2) =13a(3) =77a(4) =591a(5) =5627a(6) =64261a(7) =857901a(8) =13125559a(9) =226566107a(10) =4357258269a(11) =92408688077
External references
- oeis: A043301