G.f.: Sum_{n>=0} n! * x^n * Product_{k=1..n} (1 + k*x) / (1 + k*x + k^2*x^2).
A208237
G.f.: Sum_{n>=0} n! * x^n * Product_{k=1..n} (1 + k*x) / (1 + k*x + k^2*x^2).
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =54a(6) =223a(7) =1045a(8) =5474a(9) =31685a(10) =200895a(11) =1384470a(12) =10304431a(13) =82376101a(14) =703949762a(15) =6403761365a(16) =61784985615a(17) =630180031734
External references
- oeis: A208237