# A068669 (b-file synthesized from sequence entry) 1 1 2 2 3 3 4 5 5 7 6 11 7 13 8 17 9 23 10 31 11 37 12 53 13 71 14 73 15 113 16 131 17 137 18 173 19 311 20 313 21 317 22 373 23 1373 24 3137