1716191domain: NAppears in sequencesa(n) = binomial(n+3,6) + binomial(n+1,5) + binomial(n,5).at n=28A005732Total number of triangles visible in regular n-gon with all diagonals drawn.at n=28A006600Total number of triangles visible in a regular (2n+1)-gon with all diagonals drawn.at n=14A341441