a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+3,n-k).
A390589
a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+3,n-k).
Terms
- a(0) =1a(1) =6a(2) =46a(3) =376a(4) =3181a(5) =27492a(6) =241088a(7) =2136704a(8) =19090180a(9) =171642566a(10) =1551167806a(11) =14077358512a(12) =128208471574
External references
- oeis: A390589