a(n) = binomial(n,floor(n/2))*binomial(n+1,floor(n/2+1/2))*(1+floor(n/2))/(1+2*floor(n/2)).

A241530

a(n) = binomial(n,floor(n/2))*binomial(n+1,floor(n/2+1/2))*(1+floor(n/2))/(1+2*floor(n/2)).

Terms

    a(0) =1a(1) =2a(2) =4a(3) =12a(4) =36a(5) =120a(6) =400a(7) =1400a(8) =4900a(9) =17640a(10) =63504a(11) =232848a(12) =853776a(13) =3171168a(14) =11778624a(15) =44169840a(16) =165636900a(17) =625739400a(18) =2363904400a(19) =8982836720a(20) =34134779536a(21) =130332794592a(22) =497634306624

External references