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

1,1

Comments

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

Links

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

Example

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

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 *)

Prog

(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

Crossrefs

Sequence in context: A044026 A085607 A087993 * A167328 A116247 A168108

Adjacent sequences: A062387 A062388 A062389 * A062391 A062392 A062393

Keyword

nonn,base,easy

Author

Amarnath Murthy, Jun 27 2001

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

Status

approved