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.

Showing 1-3 of 3 results.

A029785 Numbers k whose cube k^3 has no digit in common with k.

Original entry on oeis.org

2, 3, 7, 8, 22, 27, 43, 47, 48, 52, 53, 63, 68, 77, 92, 157, 172, 177, 187, 188, 192, 222, 223, 252, 263, 303, 378, 408, 423, 442, 458, 468, 477, 478, 487, 527, 552, 558, 577, 587, 588, 608, 648, 692, 707, 772, 808, 818, 823, 843, 888, 918, 922
Offset: 1

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Author

Keywords

Comments

Original name: Digits of n are not present in n^3.
Might be called "Exclusionary Cubes", although this might be reserved for terms having no duplicate digits, cf. link to rec.puzzles discussion group. In that case the largest term would be 7658 = A113951(3). - M. F. Hasler, Oct 17 2018; corrected thanks to David Radcliffe and Michel Marcus, Apr 30 2020

Examples

			k = 80800000008880080808880080088 is in the sequence because the 87-digit number k^3 has only digits 1, ..., 7 and 9. - _M. F. Hasler_, Oct 16 2018
		

Crossrefs

Programs

  • Mathematica
    Select[Range[5000], Intersection[IntegerDigits[#], IntegerDigits[#^3]]=={}&] (* Vincenzo Librandi, Oct 04 2013 *)
  • PARI
    is(n)=my(d=Set(digits(n))); setminus(d,Set(digits(n^3)))==d \\ Charles R Greathouse IV, Oct 02 2013
    
  • PARI
    is_A029785(n)=setintersect(Set(digits(n)),Set(digits(n^3)))==[] \\ M. F. Hasler, Oct 16 2018

Extensions

Name reworded by Jon E. Schoenfield and M. F. Hasler, Oct 16 2018

A109135 Least number whose n-th power is exclusionary (or 0 if no such n exists). An exclusionary n-th power m^n is one made up of digits not appearing in m, which itself consists of distinct digits.

Original entry on oeis.org

0, 2, 2, 2, 0, 2, 3, 3, 0, 3, 3, 2, 0, 2, 0, 2, 0, 0, 3, 2, 0, 2, 2, 7, 0, 2, 3, 3, 0, 0, 0, 0, 0, 2, 2, 2, 0, 0, 2, 3, 0, 2, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 2

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Author

Lekraj Beedassy, Aug 17 2005

Keywords

Comments

a(n)=0 for n=1(mod 4)=A016813.
a(4k+1) = 0. All other zeros are unproved and have been checked up to m = 1000. - David Wasserman, May 27 2008

References

  • H. Ibstedt, Solution to Problem 2623, "Exclusionary Powers", pp. 346-9 Journal of Recreational Mathematics, Vol. 32 No.4 2003-4 Baywood NY.

Crossrefs

Cf. A113951.

Extensions

More terms from David Wasserman, May 27 2008

A113952 Largest exclusionary n-th power (or 0 if no such number exists).

Original entry on oeis.org

408540845584, 449103134312, 51050010415041, 0, 606355001344, 60170087060757, 66045000696445844586496, 0, 3570467226624, 743008370688, 16777216, 0, 9012061295995008299689, 0, 1853020188851841, 0, 0, 1162261467, 1099511627776
Offset: 2

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Author

Lekraj Beedassy, Nov 09 2005

Keywords

Comments

An exclusionary n-th power m^n is one made up of digits not appearing in the root m which itself consists of distinct digits. For the corresponding root m, see A113951. In principle, no exclusionary n-th power exists for n=1(mod 4)=A016813.

Examples

			a(10)=3570467226624 because it shares no digit in common with its 10th root 18 and no number with distinct digits greater than 18 exhibits such property.
		

References

  • H. Ibstedt, Solution to Problem 2623, "Exclusionary Powers", pp. 346-9 Journal of Recreational Mathematics, Vol. 32 No.4 2003-4 Baywood NY.

Crossrefs

Showing 1-3 of 3 results.