Number of groups of order 3^n.A090091Number of groups of order 3^n.Terms a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =67a(6) =504a(7) =9310a(8) =1396077a(9) =5937876645External referencesoeis: A090091