a(n) = (1/(4*n+3)) * Sum_{k=0..n} (4*k+3) * binomial(4*n+3,n-k).
A390778
a(n) = (1/(4*n+3)) * Sum_{k=0..n} (4*k+3) * binomial(4*n+3,n-k).
Terms
- a(0) =1a(1) =4a(2) =23a(3) =152a(4) =1084a(5) =8116a(6) =62866a(7) =499376a(8) =4044740a(9) =33272912a(10) =277200791a(11) =2333900664a(12) =19826702388a(13) =169725523288
External references
- oeis: A390778