The number of interior points that are intersections of exactly two chords for a 2n-gon where all its vertices are joined by lines (cf. A006561).
A352144
The number of interior points that are intersections of exactly two chords for a 2n-gon where all its vertices are joined by lines (cf. A006561).
Terms
- a(0) =0a(1) =1a(2) =12a(3) =40a(4) =140a(5) =228a(6) =644a(7) =1168a(8) =1512a(9) =3360a(10) =5280a(11) =6144a(12) =11284a(13) =15680a(14) =13800a(15) =28448a(16) =37264a(17) =42444a(18) =60648a(19) =75720a(20) =75012a(21) =114400a(22) =138644a(23) =152064a(24) =198200a(25) =234208a(26) =254988a(27) =321048a(28) =372708a(29) =375060
External references
- oeis: A352144