a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+2,n-k).
A390547
a(n) = Sum_{k=0..n} (-1)^k * binomial(4*n-k+2,n-k).
Terms
- a(0) =1a(1) =5a(2) =37a(3) =297a(4) =2486a(5) =21335a(6) =186166a(7) =1643833a(8) =14644540a(9) =131370000a(10) =1185000829a(11) =10737583407a(12) =97663553248a(13) =891137564714
External references
- oeis: A390547