A037108 Trajectory of 3 under map n->21n+1 if n odd, n->n/2 if n even

3, 64, 32, 16, 8, 4, 2, 1, 22, 11, 232, 116, 58, 29, 610, 305, 6406, 3203, 67264, 33632, 16816, 8408, 4204, 2102, 1051, 22072, 11036, 5518, 2759, 57940, 28970, 14485, 304186, 152093, 3193954, 1596977, 33536518