%I #7 Aug 19 2021 16:59:33
%S 1,42,21,862,431,17672,8836,4418,2209,90570,45285,1856686,928343,
%T 38062064,19031032,9515516,4757758,2378879,97534040,48767020,24383510,
%U 12191755,499861956,249930978,124965489
%N Trajectory of 1 under map n->41n+1 if n odd, n->n/2 if n even
%H Harvey P. Dale, <a href="/A033976/b033976.txt">Table of n, a(n) for n = 0..1000</a>
%t NestList[If[EvenQ[#],#/2,41#+1]&,1,30] (* _Harvey P. Dale_, Aug 19 2021 *)
%K nonn
%O 0,2
%A _N. J. A. Sloane_.