%I #10 Jul 15 2021 06:29:11
%S 2857142857142857142857142857142858,
%T 4285714285714285714285714285714287,
%U 5714285714285714285714285714285716,19354838709677419354838709677419354838709677419354838709678
%N Numbers k such that k^2 is the concatenation of two numbers m and 3*m.
%Y Cf. A102567, A106497, A115527 - A115556.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Jan 25 2006