a(n) = (3^n/n!) * Product_{k=0..n-1} (3*k + 4).
A004991
a(n) = (3^n/n!) * Product_{k=0..n-1} (3*k + 4).
Terms
- a(0) =1a(1) =12a(2) =126a(3) =1260a(4) =12285a(5) =117936a(6) =1120392a(7) =10563696a(8) =99034650a(9) =924323400a(10) =8596207620a(11) =79710288840a(12) =737320171770
External references
- oeis: A004991