a(n) = s!/(s-n)! where s = (n*(n+1)/2)+1.
A129893
a(n) = s!/(s-n)! where s = (n*(n+1)/2)+1.
Terms
- a(0) =1a(1) =2a(2) =12a(3) =210a(4) =7920a(5) =524160a(6) =53721360a(7) =7866331200
External references
- oeis: A129893
A129893
a(n) = s!/(s-n)! where s = (n*(n+1)/2)+1.