a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+1,n-k).
A386821
a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+1,n-k).
Terms
- a(0) =1a(1) =4a(2) =29a(3) =230a(4) =1912a(5) =16336a(6) =142102a(7) =1251866a(8) =11132876a(9) =99728360a(10) =898558685a(11) =8134383618a(12) =73927455396a(13) =674099027248
External references
- oeis: A386821