This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A062390 #15 Jun 29 2018 03:58:26
%S A062390 45,54,495,594,4545,4995,5454,5994,45045,49995,54054,59994,450045,
%T A062390 454545,495495,499995,540054,545454,594594,599994,4500045,4549545,
%U A062390 4950495,4999995,5400054,5459454,5940594,5999994,45000045,45045045
%N A062390 Numbers k such that (k + R(k)) / (k - R(k)) = +-11 where R(k) is the digit reversal of k (A004086).
%C A062390 Are there numbers for which (k + R(k)) / (k - R(k)) is a number other than 11?
%H A062390 Harry J. Smith, <a href="/A062390/b062390.txt">Table of n, a(n) for n = 1..44</a>
%e A062390 (5994 + 4995) /(5994 - 4995) = 10989/999 = 11, so 5994 is in the sequence.
%t A062390 dr11Q[n_]:=Module[{dr=FromDigits[Reverse[IntegerDigits[n]]]},n!=dr && Abs[(n+dr)/(n-dr)]==11]; Select[Range[45100000],dr11Q] (* _Harvey P. Dale_, Oct 03 2011 *)
%o A062390 (PARI) { n=0; for (m=1, 10^9, x=m; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); if ((m + r) == 11*abs(m - r), write("b062390.txt", n++, " ", m); if (n==44, break)) ) } \\ _Harry J. Smith_, Aug 07 2009
%K A062390 nonn,base,easy
%O A062390 1,1
%A A062390 _Amarnath Murthy_, Jun 27 2001
%E A062390 Corrected formula and more terms from _Jason Earls_, Jun 29 2001
%E A062390 Definition corrected and incorrect formula deleted by _Harry J. Smith_, Aug 06 2009
%E A062390 Missing terms adding like a(5) = 4545 by _Harry J. Smith_, Aug 07 2009