a(n) = Product_{1 <= i < j <= n} (t(i) + t(j)); t = A000217 = triangular numbers.
A203511
a(n) = Product_{1 <= i < j <= n} (t(i) + t(j)); t = A000217 = triangular numbers.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =252a(4) =576576a(5) =87178291200
External references
- oeis: A203511