Iterations of "n->n/2 if n even, n->3n-1 if n odd" (A001281) starting at these numbers reach 17.

Terms

a(0) =17a(1) =21a(2) =23a(3) =25a(4) =31a(5) =33a(6) =34a(7) =37a(8) =41a(9) =42a(10) =45a(11) =46a(12) =49a(13) =50a(14) =55a(15) =61a(16) =62a(17) =66a(18) =67a(19) =68a(20) =73a(21) =74a(22) =82a(23) =83a(24) =84a(25) =90a(26) =91a(27) =92a(28) =98a(29) =99