Smallest number which requires n^2 steps in the 3x+1 problem.

Terms

a(0) =1a(1) =2a(2) =16a(3) =12a(4) =7a(5) =98a(6) =153a(7) =169a(8) =673a(9) =350a(10) =107a(11) =129a(12) =649a(13) =2110a(14) =4763a(15) =6919a(16) =6943a(17) =158299a(18) =71310a(19) =724686a(20) =845223a(21) =665215a(22) =2157291a(23) =4468260a(24) =5978623a(25) =34385063a(26) =21015006a(27) =301695657a(28) =489853918a(29) =568097511