a(n) = Sum_{k=0..n} 2^k * binomial(k+2,2) * binomial(k,n-k)^2.

A391676

a(n) = Sum_{k=0..n} 2^k * binomial(k+2,2) * binomial(k,n-k)^2.

Terms

    a(0) =1a(1) =6a(2) =30a(3) =176a(4) =984a(5) =5232a(6) =27312a(7) =140160a(8) =707952a(9) =3531168a(10) =17428896a(11) =85249536a(12) =413738240a(13) =1994390016a(14) =9556560384a(15) =45550854144a(16) =216094481664

External references