a(1) = 1, a(2) = 2; for n>2, a(n) = sum_{r=1..n} {sum of all previous terms taken r at a time}.
A089709
a(1) = 1, a(2) = 2; for n>2, a(n) = sum_{r=1..n} {sum of all previous terms taken r at a time}.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =36a(4) =360a(5) =6480a(6) =220320a(7) =14541120a(8) =1890345600a(9) =487709164800
External references
- oeis: A089709