G.f.: Sum_{n>=0} x^n / Product_{k=n*(n-1)/2+1..n*(n+1)/2} (1 - k*x).
A249637
G.f.: Sum_{n>=0} x^n / Product_{k=n*(n-1)/2+1..n*(n+1)/2} (1 - k*x).
Terms
- a(0) =1a(1) =1a(2) =2a(3) =7a(4) =36a(5) =252a(6) =2278a(7) =25479a(8) =343318a(9) =5455963a(10) =100504720a(11) =2117265242a(12) =50438185262
External references
- oeis: A249637