A037107 Trajectory of 3 under map n->19n+1 if n odd, n->n/2 if n even

3, 58, 29, 552, 276, 138, 69, 1312, 656, 328, 164, 82, 41, 780, 390, 195, 3706, 1853, 35208, 17604, 8802, 4401, 83620, 41810, 20905, 397196, 198598, 99299, 1886682, 943341, 17923480, 8961740, 4480870