a(n) = Sum_{k=0..floor(n/3)} binomial(4*n-3*k+1,n-3*k).
A390704
a(n) = Sum_{k=0..floor(n/3)} binomial(4*n-3*k+1,n-3*k).
Terms
- a(0) =1a(1) =5a(2) =36a(3) =287a(4) =2394a(5) =20502a(6) =178641a(7) =1575753a(8) =14027013a(9) =125753020a(10) =1133772056a(11) =10269202482a(12) =93371557501a(13) =851728271931
External references
- oeis: A390704