491840

Appears in sequences

• a(n) = T(n,n-6), array T as in A055818.at n=19A055823
• Number of polygon edges formed when every pair of vertices of a regular n-gon are joined by an infinite line.at n=39A344899
• Number of polygon edges formed when every pair of vertices of a regular 2n-gon are joined by an infinite line.at n=19A347322