The Collatz or 3x+1 map: a(n) = n/2 if n is even, 3n + 1 if n is odd.

Terms

a(0) =0a(1) =4a(2) =1a(3) =10a(4) =2a(5) =16a(6) =3a(7) =22a(8) =4a(9) =28a(10) =5a(11) =34a(12) =6a(13) =40a(14) =7a(15) =46a(16) =8a(17) =52a(18) =9a(19) =58a(20) =10a(21) =64a(22) =11a(23) =70a(24) =12a(25) =76a(26) =13a(27) =82a(28) =14a(29) =88