a(n) = (3*a(n-1)*a(n-4) - a(n-2)*a(n-3)) / a(n-5).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =5a(7) =13a(8) =29a(9) =109a(10) =629a(11) =4274a(12) =23329a(13) =170353a(14) =2034385a(15) =35152177a(16) =494532481a(17) =7768108946a(18) =176258003381