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 1-5 of 5 results.

A103173 Numbers k such that the decimal digits of k are not present in k^2, k^3, or k^4.

Original entry on oeis.org

2, 3, 7, 8, 53, 77
Offset: 1

Views

Author

Labos Elemer, Feb 28 2005

Keywords

Comments

No more terms exist below 10^100. The last five digits of any larger term must be 75557, 85557, 88787, 88188, 88988 or 98988. - Hagen von Eitzen, Jun 16 2009

Examples

			For k=77, the 1st through 4th powers are {77, 5929, 456533, 35153041}.
Digits of k appear first in the 5th powers {32, 243, 16807, 32768, 418195493, 2706784157}.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[10^3],ContainsNone[IntegerDigits[#],Union[IntegerDigits[#^2],IntegerDigits[#^3],IntegerDigits[#^4]]]&] (* James C. McMahon, Jan 17 2024 *)

A253602 Numbers n such that the smallest exponent k for n and n^k to have common digits is 4.

Original entry on oeis.org

22, 47, 92, 157, 187, 188, 192, 552, 558, 577, 707, 772, 922, 2522, 8338, 17177, 66888, 575757, 929522, 1717177, 8888588
Offset: 1

Views

Author

Michel Marcus, Jan 05 2015

Keywords

Examples

			22^2=484 and 22^3=10648 have no digits in common with 22, but 22^4=234256 has some, so 22 is in the sequence.
		

Crossrefs

Programs

  • PARI
    a253600(n) = {sd = Set(vecsort(digits(n))); k=2; while (#setintersect(sd, Set(vecsort(digits(n^k)))) == 0, k++); k;}
    isok(n) = a253600(n) == 4;

A029791 Squares k such that digits of sqrt(k) are not present in k or k^(3/2).

Original entry on oeis.org

4, 9, 49, 64, 484, 2209, 2809, 5929, 8464, 24649, 34969, 35344, 36864, 304704, 311364, 332929, 499849, 595984, 850084, 6360484, 69522244, 295049329, 4474004544, 331496123049, 864011148484, 2948696849329, 79006996633744
Offset: 1

Views

Author

Keywords

Crossrefs

Formula

a(n) = A029790(n)^2. - Andrew Howroyd, Aug 11 2024

Extensions

Offset corrected by Andrew Howroyd, Aug 11 2024

A029792 Cubes k such that digits of cube root of k are not present in k^(2/3) or k.

Original entry on oeis.org

8, 27, 343, 512, 10648, 103823, 148877, 456533, 778688, 3869893, 6539203, 6644672, 7077888, 168196608, 173741112, 192100033, 353393243, 460099648, 783777448, 16041140648, 579676470472, 5068062324233, 299257215939072
Offset: 1

Views

Author

Keywords

Crossrefs

Formula

a(n) = A029790(n)^3. - Andrew Howroyd, Aug 11 2024

Extensions

Offset corrected by Andrew Howroyd, Aug 11 2024

A030090 Primes p such that digits of p do not appear in p^2 or p^3 (probably finite).

Original entry on oeis.org

2, 3, 7, 47, 53, 157, 577
Offset: 1

Views

Author

Keywords

Comments

No additional terms in the first 1 million primes. - Harvey P. Dale, Apr 25 2018

Crossrefs

Primes in A029790.

Programs

  • Mathematica
    Select[Prime[Range[1000000]],Intersection[Union[Flatten[ IntegerDigits/@ {#^2,#^3}]],IntegerDigits[#]] == {}&] (* Harvey P. Dale, Apr 25 2018 *)

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024
Showing 1-5 of 5 results.