a(n) = binomial(2^n + 2*n + 1, n).A132686a(n) = binomial(2^n + 2*n + 1, n).Terms a(0) =1a(1) =5a(2) =36a(3) =455a(4) =12650a(5) =962598a(6) =237093780a(7) =209004408899External referencesoeis: A132686