cp's OEIS Frontend

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.

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A094676 a(n) = least number m such that the quotient m/n is obtained merely by shifting the leftmost digit of m to the right end and the second digit of m is not zero.

Original entry on oeis.org

1, 210526315789473684, 3103448275862068965517241379, 410256, 714285, 6101694915254237288135593220338983050847457627118644067796, 7101449275362318840579, 8101265822784, 91011235955056179775280898876404494382022471
Offset: 1

Views

Author

Lekraj Beedassy, Jun 07 2004

Keywords

Comments

Here when the leftmost digit of m is shifted to the right end the number of digits may not decrease - compare A097717.
Least n-transposable number. A k-transposable number, 1 <= k <= 9, is one which is k times the number obtained when the leftmost digit is moved to the end.

Examples

			a(4) = 410256 = 4*102564.
		

References

  • H. Camous, Jouer Avec Les Maths, "Chassez le naturel", Section I, Problem 3 pp. 20; 31-2, Les Editions D'Organisation, Paris 1984.
  • L. A. Graham, Ingenious Mathematical Problems and Methods, "End At The Beginning", Problem 72 pp. 44; 212-3, Dover NY 1959.

Crossrefs

Formula

a(n) = n prepended to n*(10^m - n)/(10*n - 1), where m = A094224(n) - 1.

Extensions

Edited by N. J. A. Sloane, Apr 13 2009
a(5) corrected by Emilio Martín, Jul 28 2022

A159774 Least number m, written in base n, such that m/2 is obtained merely by shifting the leftmost digit of m to the right end, and 2m by shifting the rightmost digit of m to the left end, digits defined in base n.

Original entry on oeis.org

1012, 102, 102342, 1031345242, 103524563142, 1042, 10467842, 105263157894736842, 316, 10631694842
Offset: 3

Views

Author

William A. Hoffman III (whoff(AT)robill.com), Apr 21 2009

Keywords

Comments

10(b2) and 31(b5) do not both halve and double by rotations. No 2-digit answer can meet the description, so the sequence begins with a base 3 value.

Examples

			1042(b8)/2 = 421(b8) and 1042(b8)*2 = 2104(b8)
316 (base 11) = 380 (base 10), 163 (base 11) = 190 (base 10), 631 (base 11) = 760 (base 10).
		

Crossrefs

See A147514 for these numbers written in base 10.

Extensions

Offset corrected by N. J. A. Sloane, Apr 23 2009
a(11) corrected. To indicate that terms from base n=13 on need digits larger than 9, keywords fini, full added. - Ray Chandler and R. J. Mathar, Apr 23 2009
Edited by Ray Chandler, May 02 2009
Showing 1-2 of 2 results.