Irregular triangle T(n,k) (n >= 0, k >= 2) read by rows. Consider the planar graph formed from an equilateral triangle with n equally spaced points placed on each edge, as discussed in A092867(n+1). Then T(n,k) is the number of interior points where exactly k chords cross.

A366479

Irregular triangle T(n,k) (n >= 0, k >= 2) read by rows. Consider the planar graph formed from an equilateral triangle with n equally spaced points placed on each edge, as discussed in A092867(n+1). Then T(n,k) is the number of interior points where exactly k chords cross.