%I #13 Jul 18 2021 06:48:08
%S 81,77394227,89158933,36623663376237623663376335,
%T 37633762366336633762366235,62366237633663366237633761,
%U 63376336623762376336623661,86194223018927804587702128
%N Numbers k such that k*(k+5) gives the concatenation of two numbers m and m-3.
%e 89158933 * 89158938 = 79493157//79493154, where // denotes concatenation.
%Y Cf. A028557, A116099, A116261, A116267, A116269, A116276.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Feb 06 2006