Rectilinear crossing number of complete graph on n nodes.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =3a(6) =9a(7) =19a(8) =36a(9) =62a(10) =102a(11) =153a(12) =229a(13) =324a(14) =447a(15) =603a(16) =798a(17) =1029a(18) =1318a(19) =1657a(20) =2055a(21) =2528a(22) =3077a(23) =3699a(24) =4430a(25) =5250a(26) =6180