a(n) = (binomial(2*n, n)^2 + binomial(2*n, n))/2.
A037967
a(n) = (binomial(2*n, n)^2 + binomial(2*n, n))/2.
Terms
- a(0) =1a(1) =3a(2) =21a(3) =210a(4) =2485a(5) =31878a(6) =427350a(7) =5891028a(8) =82824885a(9) =1181976510a(10) =17067482146a(11) =248817506028
External references
- oeis: A037967