%I #9 Jul 15 2021 09:15:17
%S 7142857142857142857143,14285714285714285714286,
%T 21428571428571428571429,
%U 730337078651685393258426966292134831460674157303370786517
%N Numbers k such that k^2 is the concatenation of two numbers 5*m and m.
%e 7142857142857142857143^2 = 5102040816326530612245_1020408163265306122449.
%Y Cf. A102567, A106497, A115527 - A115556.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Jan 25 2006
%E Definition modified by _Georg Fischer_, Jul 26 2019