A116258
Numbers k such that k*(k+9) gives the concatenation of two numbers m and m-5.
Original entry on oeis.org
8444, 8809, 69125298546226023970, 69855225553525294043, 74604750601020544518, 75334677608319814591, 92496418993920707745, 93226346001219977818, 97975871048715228293, 98705798056014498366
Offset: 1
8809 * 8818 = 7767//7762, where // denotes concatenation.
A116351
Numbers k such that k*(k+5) gives the concatenation of two numbers m and m+9.
Original entry on oeis.org
8446, 8811, 69125298546226023972, 69855225553525294045, 74604750601020544520, 75334677608319814593, 92496418993920707747, 93226346001219977820, 97975871048715228295, 98705798056014498368
Offset: 1
8811 * 8816 = 7767//7776, where // denotes concatenation.