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 1-6 of 6 results.

A052071 a(n)^3 is the smallest cube whose digits occur with the same frequency n.

Original entry on oeis.org

0, 11, 888, 2830479, 120023142, 6351783105, 267745815817, 13280759167047
Offset: 1

Views

Author

Patrick De Geest, Jan 15 2000

Keywords

Examples

			2830479^3 = 22676697737363992239 and its digits 2, 3, 6, 7 and 9 each occur four times.
		

Crossrefs

Programs

  • Mathematica
    Table[i = 0;
    While[x = i^3; Union@DeleteCases[DigitCount[x], 0] != {n}, i++];
    i, {n, 7}] (* Robert Price, Oct 12 2019 *)

Extensions

Offset corrected by Michel Marcus, Aug 12 2015
a(7) from Giovanni Resta, Aug 19 2018
a(8) from Mihael Tunik, May 26 2025

A052070 Smallest square all of whose digits occur with the same frequency n.

Original entry on oeis.org

0, 7744, 100220121, 1001481404808481, 269996262622969, 445646655445456656, 114811414848448481881, 425425422552255452244544, 244848282488224248488284224, 610016161160606006011116601600
Offset: 1

Views

Author

Patrick De Geest, Jan 15 2000

Keywords

Examples

			1001481404808481 (= 31646191^2) and its digits 0, 1, 4 and 8 each occur four times.
		

Crossrefs

Programs

  • Mathematica
    Table[i = 0;
    While[x = i^2; Union@DeleteCases[DigitCount[x], 0] != {n}, i++];
    x, {n, 10}] (* Robert Price, Oct 12 2019 *)

Extensions

Two more terms from Jon E. Schoenfield, Oct 11 2008
Offset corrected by Michel Marcus, Aug 12 2015
a(10) from Giovanni Resta, Aug 19 2018

A052093 a(n)^4 is the smallest fourth power whose decimal expansion digits occur with same frequency n.

Original entry on oeis.org

0, 207, 130398, 5694207, 426424828, 18304641024, 1002719491659
Offset: 1

Views

Author

Patrick De Geest, Jan 15 2000

Keywords

Comments

Terms calculated by Jeff Heleen.

Examples

			207^4 = 1836036801 and digits 0,1,3,6 and 8 each occur twice.
		

Crossrefs

Programs

Extensions

Offset corrected by Michel Marcus, Aug 12 2015
a(6) corrected and a(7) from Michael S. Branicky, Dec 17 2020

A052060 Numbers n such that the digits of 2^n occur with the same frequency.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 29
Offset: 1

Views

Author

Patrick De Geest, Jan 15 2000

Keywords

Comments

Previous name was "Smallest power of 2 whose digits occur with same frequency n".
Next term > 3597.
Not multiplicative since a(18) is supposedly > 3597, but a(2) = 2 and a(9) = 9. - David W. Wilson, Jun 12 2005
From Robert Israel, Aug 14 2015: (Start)
Next term (if any) > 10^4.
It is highly likely that the sequence is finite. For each m, there are at most 4 powers of 2 with m digits. If m is large, of the 9*10^m numbers with m digits, there are at most about c * 10^m/m^(9/2) with equal digit frequencies where c is a constant (this comes from the case where there all 10 digits are represented with frequencies m/10). Thus heuristically the expected number of m-digit powers of 2 with equal digit frequencies decreases like m^(-9/2), and this has a finite sum. (End)

Examples

			E.g., 2^29 = 536870912 where each digit occurs once in this case.
		

Crossrefs

Programs

  • Maple
    filter:= proc(n) local x,i,P;
    P:= add(x^i,i=convert(2^n,base,10));
    nops({coeffs(P,x)})=1
    end proc:
    select(filter, [$1..10^4]); # Robert Israel, Aug 14 2015

Extensions

Name and offset corrected by Michel Marcus, Aug 12 2015

A054212 a(n)^5 is the smallest fifth power whose decimal digits occur with same frequency n.

Original entry on oeis.org

0, 2955, 49995, 10365589, 75418384, 2592877410, 100661113419, 3989342709778, 2826734132736, 78074715540102
Offset: 1

Views

Author

Patrick De Geest, Feb 15 2000

Keywords

Comments

Terms calculated by Jeff Heleen.
Next term > 2.5*10^17 - Frank A. Stevenson, Feb 02 2024

Examples

			2955^5 = 225313610074846875 and digits 0, 1, 2, 3, 4, 5, 6, 7, and 8 each occur twice.
		

Crossrefs

Programs

  • Python
    def agen(POW=5):
      n = 1
      while True:
        k = 0
        while True:
          kpowstr = str(pow(k, POW))
          q, r = divmod(len(kpowstr), n)
          if r == 0:
            ok = True
            for d in set(kpowstr):
              if kpowstr.count(d) != n:
                ok = False; break
            if ok: break
            k += 1
          else: # go to next multiple of n digits: (q+1)*n
            k = max(k+1, int((10**((q+1)*n-1))**(1/POW)))
        yield k
        n += 1
    g = agen() # call with POW=4, 3, 2 for A052093, A052071, A052069
    print([next(g) for n in range(1, 5)]) # Michael S. Branicky, Dec 17 2020

Extensions

Offset corrected by Michel Marcus, Aug 12 2015
a(7)-a(8) from Michael S. Branicky, Dec 17 2020
a(9)-a(10) from Frank A. Stevenson, Jan 02 2024

A054213 Smallest fifth powers whose decimal expansion digits occur with same frequency n.

Original entry on oeis.org

0, 225313610074846875, 312343781246875156246875, 119665765800843104737370354851986949, 2439979134100773706931016420916722663424, 117195225794292252449115584887987847895470100000, 10334956410016814668660393585195309584134568401459883099, 1010431164918909763339703798486498718473866680301776494470190368
Offset: 1

Views

Author

Patrick De Geest, Feb 15 2000

Keywords

Comments

Terms calculated by Jeff Heleen.

Examples

			2955^5 = 225313610074846875 and digits 0, 1, 2, 3, 4, 5, 6, 7, and 8 each occur twice.
		

Crossrefs

Subsequence of A000584.

Programs

Extensions

Offset corrected by Michel Marcus, Aug 12 2015
a(6)-a(8) from Michael S. Branicky, Dec 17 2020
Showing 1-6 of 6 results.