a(n) = (1+(-1)^n)/2*4^n*(C((3*n)/2-1,n))+(1-(-1)^n)/2*((C((3*n-1)/2,n))*(C(3*n-1,(3*n-1)/2)))/(C(n-1,(n-1)/2)).
A348618
a(n) = (1+(-1)^n)/2*4^n*(C((3*n)/2-1,n))+(1-(-1)^n)/2*((C((3*n-1)/2,n))*(C(3*n-1,(3*n-1)/2)))/(C(n-1,(n-1)/2)).
Terms
- a(0) =1a(1) =2a(2) =16a(3) =140a(4) =1280a(5) =12012a(6) =114688a(7) =1108536a(8) =10813440a(9) =106234700a(10) =1049624576a(11) =10418726760a(12) =103817412608
External references
- oeis: A348618