A116348 Numbers k such that k*(k+1) gives the concatenation of two numbers m and m+9.
10, 90, 3678, 6322, 8788, 48745, 51255, 87619, 3762556, 6237444, 9217102, 3266298276, 3520463766, 6479536234, 6733701724, 8063694650, 8317860140, 4689524709430934476, 5310475290569065524, 7416797436703661749
Offset: 1