The number of concave polygon classes.

Terms

a(0) =0a(1) =1a(2) =3a(3) =8a(4) =14a(5) =29a(6) =53a(7) =100a(8) =180a(9) =343a(10) =623a(11) =1172a(12) =2182a(13) =4105a(14) =7701a(15) =14590a(16) =27584a(17) =52475a(18) =99867a(19) =190732a(20) =364710a(21) =699237a(22) =1342169a(23) =2581412a(24) =4971052a(25) =9587563a(26) =18512775a(27) =35792550a(28) =69273650a(29) =134219777