Numbers k such that k * (k+1) is the concatenation of a number m with itself.

Terms

a(0) =363a(1) =637a(2) =714a(3) =923a(4) =8905a(5) =81818a(6) =336633a(7) =663367a(8) =7272727a(9) =76470589a(10) =333666333a(11) =405436668a(12) =428571429a(13) =447710185a(14) =454545454a(15) =473684211a(16) =526315789a(17) =545454546a(18) =552289815a(19) =571428571a(20) =594563332a(21) =666333667a(22) =692307693a(23) =711446449a(24) =762237762a(25) =834008097a(26) =859982123a(27) =879120879a(28) =902255640a(29) =974025975