Central elements in the 5-Pascal triangle A028313.

Terms

a(0) =1a(1) =5a(2) =12a(3) =38a(4) =130a(5) =462a(6) =1680a(7) =6204a(8) =23166a(9) =87230a(10) =330616a(11) =1259700a(12) =4820452a(13) =18513068a(14) =71318400a(15) =275467320a(16) =1066432950a(17) =4136847390a(18) =16075953960a(19) =62570669700a(20) =243882320220a(21) =951797460900