a(1) = 1; a(n) = Sum_{k=1..n-1} a(n-k) * Sum_{d|k} a(d)*a(k/d).
A307816
a(1) = 1; a(n) = Sum_{k=1..n-1} a(n-k) * Sum_{d|k} a(d)*a(k/d).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =11a(4) =46a(5) =201a(6) =928a(7) =4399a(8) =21431a(9) =106399a(10) =536896a(11) =2744532a(12) =14185314a(13) =73999955a(14) =389131156a(15) =2060478226a(16) =10976863244a(17) =58792036053a(18) =316397505099
External references
- oeis: A307816