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

Terms

a(0) =0a(1) =2a(2) =1a(3) =5a(4) =2a(5) =8a(6) =3a(7) =11a(8) =4a(9) =14a(10) =5a(11) =17a(12) =6a(13) =20a(14) =7a(15) =23a(16) =8a(17) =26a(18) =9a(19) =29a(20) =10a(21) =32a(22) =11a(23) =35a(24) =12a(25) =38a(26) =13a(27) =41a(28) =14a(29) =44