Pyramid P(n, t, d) read by planes and rows, for 0 <= t+d <= n: number of ways n triples can sit in a row so that exactly t triples are together and exactly d triples are separated into a couple and a loner.

A192990

Pyramid P(n, t, d) read by planes and rows, for 0 <= t+d <= n: number of ways n triples can sit in a row so that exactly t triples are together and exactly d triples are separated into a couple and a loner.