A pattern number (90_{n})911 with n=11*k+5, for k=3219 and
thus n=35414, whose square yields a concatenation of two
consecutives of the form (T)_(T+1).
E.g.: 9090909090911 ^ 2 = 8264462809920_8264462809921 .
Source see file em152.htm at www.worldofnumbers.com.
PRP to base 3, 5 and 7 using PFGW Version 20031222.

To be completed...