a(0) = a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k) * a(n-k-3).
A333497
a(0) = a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k) * a(n-k-3).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =8a(7) =18a(8) =48a(9) =144a(10) =456a(11) =1560a(12) =5808a(13) =23184a(14) =98160a(15) =440832a(16) =2101824a(17) =10588608a(18) =56104128a(19) =312013440a(20) =1818498816a(21) =11082682368a(22) =70467474816a(23) =466680045312
External references
- oeis: A333497