a(n) = Product_{i=1..n} sigma(i) * Sum_{i=1..n} 1/sigma(i).
A067577
a(n) = Product_{i=1..n} sigma(i) * Sum_{i=1..n} 1/sigma(i).
Terms
- a(0) =1a(1) =4a(2) =19a(3) =145a(4) =954a(5) =11952a(6) =101664a(7) =1573344a(8) =21179232a(9) =390661056a(10) =4857760512a(11) =138055228416
External references
- oeis: A067577