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.

A355060 Perfect powers whose digits are in strictly increasing order.

Original entry on oeis.org

4, 8, 9, 16, 25, 27, 36, 49, 125, 128, 169, 256, 289, 1369, 13456, 13689, 134689
Offset: 1

Views

Author

Jon E. Schoenfield, Jun 16 2022

Keywords

Comments

I.e., numbers of the form b^k with b > 1 and k > 1 in whose base-10 expansion each digit is greater than the previous digit.

Crossrefs

Programs

  • Mathematica
    perfectPowerQ[n_] := GCD @@ FactorInteger[n][[All, 2]] > 1; (* A001597 *) Select[Range[135000], perfectPowerQ[#] && AllTrue[Differences[IntegerDigits[#]],Positive] &] (* Stefano Spezia, Jul 01 2025 *)

A385516 Perfect powers whose digits are in strictly decreasing order.

Original entry on oeis.org

1, 4, 8, 9, 32, 64, 81, 841, 961
Offset: 1

Views

Author

Stefano Spezia, Jul 01 2025

Keywords

Crossrefs

Programs

  • Mathematica
    perfectPowerQ[n_] := n==1 || GCD @@ FactorInteger[n][[All, 2]] > 1; (* A001597 *) Select[Range[1000], perfectPowerQ[#] && Max[Differences[IntegerDigits[#]]]<0 &]

A385517 Perfect powers whose digits are in nonincreasing order.

Original entry on oeis.org

1, 4, 8, 9, 32, 64, 81, 100, 400, 441, 841, 900, 961, 1000, 6400, 7744, 7776, 8000, 8100, 10000, 40000, 44100, 64000, 84100, 90000, 96100, 100000, 640000, 774400, 810000, 1000000, 3200000, 4000000, 4410000, 8000000, 8410000, 8874441, 9000000, 9610000, 9853321, 10000000
Offset: 1

Views

Author

Stefano Spezia, Jul 01 2025

Keywords

Crossrefs

Programs

  • Mathematica
    perfectPowerQ[n_] :=n==1 || GCD @@ FactorInteger[n][[All, 2]] > 1; (* A001597 *) Select[Range[10^6], perfectPowerQ[#] && Max[Differences[IntegerDigits[#]]]<1 &]
Showing 1-3 of 3 results.