Maximal term in Collatz-iteration started at 3^n.

Terms

a(0) =16a(1) =52a(2) =9232a(3) =244a(4) =9232a(5) =2464a(6) =10528a(7) =19684a(8) =88576a(9) =2270104a(10) =1008916a(11) =1594324a(12) =7174456a(13) =65451076a(14) =64570084a(15) =129140164a(16) =1570824736a(17) =1961316232a(18) =8825923024a(19) =10460353204a(20) =47071589416a(21) =105911076184a(22) =423644304724