A116231 Numbers k such that k*(k+9) gives the concatenation of two numbers m and m-9.
7, 63, 42752, 57240, 75422, 425071, 574921, 979527, 4301392, 5698600, 7028665, 4925000746, 5074999246, 7748266573, 8511881483, 8814851183, 7059602159671, 7106167933827, 7439286611620, 7485852385776, 46791112884924
Offset: 1