a(n)=If[IntegerQ[((6*n - 4)/( n + 1))*a(n - 1)], ((6*n - 4)/(n + 1))* a(n - 1), If[IntegerQ[((4*n - 2)/(n + 1))*a( n - 1)], ((4*n - 2)/(n + 1))*a(n - 1), n*a(n - 1)]].
A155581
a(n)=If[IntegerQ[((6*n - 4)/( n + 1))*a(n - 1)], ((6*n - 4)/(n + 1))* a(n - 1), If[IntegerQ[((4*n - 2)/(n + 1))*a( n - 1)], ((4*n - 2)/(n + 1))*a(n - 1), n*a(n - 1)]].
Terms
- a(0) =1a(1) =1a(2) =2a(3) =7a(4) =28a(5) =84a(6) =384a(7) =1824a(8) =6080a(9) =30400a(10) =304000a(11) =1064000a(12) =12768000a(13) =67488000a(14) =359936000a(15) =1934656000a(16) =30954496000a(17) =526226432000
External references
- oeis: A155581