A062390 Numbers k such that (k + R(k)) / (k - R(k)) = +-11 where R(k) is the digit reversal of k (A004086).

45, 54, 495, 594, 4545, 4995, 5454, 5994, 45045, 49995, 54054, 59994, 450045, 454545, 495495, 499995, 540054, 545454, 594594, 599994, 4500045, 4549545, 4950495, 4999995, 5400054, 5459454, 5940594, 5999994, 45000045, 45045045

Offset: 1

Author

Amarnath Murthy, Jun 27 2001

Keywords

• nonn
• base
• easy

Comments

Are there numbers for which (k + R(k)) / (k - R(k)) is a number other than 11?

Examples

			(5994 + 4995) /(5994 - 4995) = 10989/999 = 11, so 5994 is in the sequence.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..44

Programs

Mathematica

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 *)

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

Extensions

Corrected formula and more terms from Jason Earls, Jun 29 2001

Definition corrected and incorrect formula deleted by Harry J. Smith, Aug 06 2009

Missing terms adding like a(5) = 4545 by Harry J. Smith, Aug 07 2009