Number of nodes in regular n-gon with all diagonals drawn.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =10a(5) =19a(6) =42a(7) =57a(8) =135a(9) =171a(10) =341a(11) =313a(12) =728a(13) =771a(14) =1380a(15) =1393a(16) =2397a(17) =1855a(18) =3895a(19) =3861a(20) =6006a(21) =5963a(22) =8878a(23) =7321a(24) =12675a(25) =12507a(26) =17577a(27) =17277a(28) =23780a(29) =16831