A116329 Numbers k such that k*(k+1) gives the concatenation of two numbers m and m+6.
387, 431, 569, 613, 816, 4523, 5477, 90912, 316834, 683166, 3636366, 6363634, 82352944, 331668334, 368421055, 395604393, 442767756, 461538464, 488721802, 511278198, 538461536, 557232244, 604395607, 631578945, 668331666
Offset: 1