a(n) = B(n+2)-3*B(n+1)+B(n), where B(i) are the Bell numbers A000110.
A226506
a(n) = B(n+2)-3*B(n+1)+B(n), where B(i) are the Bell numbers A000110.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =12a(4) =62a(5) =320a(6) =1712a(7) =9604a(8) =56674a(9) =351792a(10) =2293862a(11) =15682216a(12) =112179608a(13) =837905016a(14) =6522165834a(15) =52807401908a(16) =443962338894
External references
- oeis: A226506