Maximal term in Collatz-iteration started at 3^n+1.

Terms

a(0) =2a(1) =4a(2) =16a(3) =52a(4) =9232a(5) =244a(6) =9232a(7) =2464a(8) =10528a(9) =19684a(10) =88576a(11) =2270104a(12) =1008916a(13) =1594324a(14) =7174456a(15) =65451076a(16) =64570084a(17) =129140164a(18) =1570824736a(19) =1961316232a(20) =8825923024a(21) =10460353204a(22) =47071589416a(23) =105911076184a(24) =423644304724