Largest number which requires n iterations of the unitary totient function (A047994) to reach 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =14a(4) =42a(5) =86a(6) =186a(7) =462a(8) =930a(9) =1986a(10) =4170a(11) =6510a(12) =14682a(13) =29366a(14) =50342a(15) =73410a(16) =189498a(17) =287654a(18) =491190a(19) =849570a(20) =1699142a(21) =2433878a(22) =4280774a(23) =7978218a(24) =14442690a(25) =25900142a(26) =44400390a(27) =78492954a(28) =123958794a(29) =228018066