a(0) = a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} Stirling2(n-3,k) * a(k).
A336020
a(0) = a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} Stirling2(n-3,k) * a(k).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =5a(7) =15a(8) =53a(9) =222a(10) =1115a(11) =6698a(12) =47243a(13) =382187a(14) =3480048a(15) =35251942a(16) =394839407a(17) =4875966656a(18) =66282636371a(19) =989985346269
External references
- oeis: A336020