a(n) = Sum_{j=0..n} Sum_{k=0..n} binomial(n,j)*binomial(n,k)*max(j,k).

A100511

a(n) = Sum_{j=0..n} Sum_{k=0..n} binomial(n,j)*binomial(n,k)*max(j,k).

Terms

    a(0) =0a(1) =3a(2) =22a(3) =126a(4) =652a(5) =3190a(6) =15060a(7) =69356a(8) =313624a(9) =1398438a(10) =6166660a(11) =26948548a(12) =116888232a(13) =503811516a(14) =2159864392a(15) =9216445080a(16) =39168381488a(17) =165864540934a(18) =700151508324

External references