Numbers k such that k*(k+5) gives the concatenation of a number m with itself.

Terms

a(0) =6a(1) =96a(2) =385a(3) =429a(4) =567a(5) =611a(6) =814a(7) =996a(8) =4521a(9) =5475a(10) =9996a(11) =90910a(12) =99996a(13) =316832a(14) =683164a(15) =999996a(16) =3636364a(17) =6363632a(18) =9999996a(19) =82352942a(20) =99999996a(21) =331668332a(22) =368421053a(23) =395604391a(24) =442767754a(25) =461538462a(26) =488721800a(27) =511278196a(28) =538461534a(29) =557232242