# A005406 (b-file synthesized from sequence entry) 1 1 2 3 3 6 4 13 5 25 6 49 7 91 8 170 9 309 10 558 11 992 12 1752 13 3062 14 5317 15 9166 16 15712 17 26784 18 45447 19 76775 20 129203 21 216662 22 362177 23 603671 24 1003566 25 1664389 26 2754382 27 4549207 28 7500096 29 12344840 30 20288723 31 33298979 32 54584077 33 89373081 34 146182754