a(n) = (n+2)*Sum_{i=0..n}(binomial(3*n-2*i+1, n-i)/(2*n-i+2)).
A277956
a(n) = (n+2)*Sum_{i=0..n}(binomial(3*n-2*i+1, n-i)/(2*n-i+2)).
Terms
- a(0) =1a(1) =4a(2) =19a(3) =101a(4) =573a(5) =3382a(6) =20483a(7) =126292a(8) =788878a(9) =4976489a(10) =31635811a(11) =202354517a(12) =1300880374a(13) =8398175713a(14) =54409200963a(15) =353571026085
External references
- oeis: A277956