A116274 Numbers k such that k*(k+3) gives the concatenation of two numbers m and m-2.
9, 99, 362, 636, 713, 922, 999, 8904, 9999, 81817, 99999, 336632, 663366, 999999, 7272726, 9999999, 76470588, 99999999, 333666332, 405436667, 428571428, 447710184, 454545453, 473684210, 526315788, 545454545, 552289814
Offset: 1