418 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



Table VI — Crosspoints for Various Values of N and n 



* Minimum values. 



Equation (17) is identical to equation (16) when r = n — 1. There 

 are two cases, namely, when n = 2 and n = 3 where equation (16a) 

 gives fewer crosspoints than does equation (17). 



SEARCH FOR THE MINIMUM NUMBER OF CROSSPOINTS BETWEEN N = 

 23 AND A^ = 160 



The equations of the preceding sections furnish a means for search- 

 ing for minimum crossnet arrays. Table VI shows the results of such a 

 search up to A^ = 160. Results are indicated in unit steps from N — 

 23 to iV = 40 and for every tenth interval thereafter. At iV = 161, a 

 five-stage array requires the fewest crosspoints. 



Table VI was computed by the use of finite differences. The equations 



