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 1-10 of 12 results. Next

A052049 a(n)^2 is a square whose digits occur with an equal minimum frequency of 2.

Original entry on oeis.org

88, 478, 577, 583, 715, 836, 880, 881, 893, 3362, 3386, 3911, 4077, 4780, 5077, 5239, 5369, 5770, 5784, 5789, 5830, 5858, 6523, 6756, 6772, 6926, 6941, 7107, 7150, 7359, 7535, 7827, 8043, 8196, 8229, 8360, 8525, 8810, 8930, 8989, 9251, 9701, 9764, 9786
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Comments

There are A225428(10) = 597959 terms in this sequence. The last term is 9994363488, whose square is 99887301530267526144 = A052050(597959). - Hugo Pfoertner, May 12 2023

Examples

			577^2 = 332929, which contains each of its digits (2, 3, and 9) twice, so 577 is in this sequence.
		

Crossrefs

Programs

  • Maple
    isA052049 := proc(n) local d, k, fr, eqfr: d:=convert(n^2, base, 10): eqfr:=true: fr:=numboccur(d[1], d): if(fr=1)then return false: fi: for k from 0 to 9 do if(not member(numboccur(k, d), {fr, 0}))then eqfr:=false: break: fi: od: return eqfr: end: seq(`if`(isA052049(n), n, NULL), n=1..9800); # Nathaniel Johnston, Jun 02 2011
  • Mathematica
    ta[n_]:=DeleteDuplicates[Transpose[Tally[IntegerDigits[n^2]]][[2]]]; t ={}; Do[If[Length[x=ta[n]]==1 && x[[1]]>=2, AppendTo[t,n]],{n,9800}]; t (* Jayanta Basu, May 11 2013 *)

A045540 Numbers whose square contains an equal number of each digit that it contains.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 14, 16, 17, 18, 19, 23, 24, 25, 27, 28, 29, 31, 32, 33, 36, 37, 42, 43, 44, 48, 49, 51, 52, 53, 54, 55, 57, 59, 61, 64, 66, 69, 71, 72, 73, 74, 78, 79, 82, 84, 86, 87, 88, 89, 93, 95, 96, 98, 99, 113, 116, 117, 118, 124, 126, 128, 133, 134, 136
Offset: 1

Views

Author

Keywords

Comments

The sequence is expected to be infinite. Heuristically, if m is divisible by 10 there should be approximately constant * 10^(m/2)/m^(9/2) m-digit squares where all 10 digits have frequency m/10. - Robert Israel, Aug 14 2015

Crossrefs

Programs

  • Maple
    filter:= proc(n) local x,i,P;
    P:= add(x^i, i=convert(n^2,base,10));
    nops({coeffs(P,x)}) = 1
    end proc:
    select(filter, [$1..10^4]); # Robert Israel, Aug 14 2015
  • Mathematica
    t={}; Do[If[Length[DeleteDuplicates[Transpose[Tally[IntegerDigits[n^2]]][[2]]]]==1,AppendTo[t,n]],{n,136}]; t (* Jayanta Basu, May 10 2013 *)

A052050 Squares whose digits occur with an equal minimal frequency of 2.

Original entry on oeis.org

7744, 228484, 332929, 339889, 511225, 698896, 774400, 776161, 797449, 11303044, 11464996, 15295921, 16621929, 22848400, 25775929, 27447121, 28826161, 33292900, 33454656, 33512521, 33988900, 34316164, 42549529, 45643536, 45859984, 47969476, 48177481, 50509449, 51122500
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Comments

There are A225428(10)=597959 terms in this sequence. The last term is 99887301530267526144 = 9994363488^2. - Hugo Pfoertner, May 12 2023

Crossrefs

Programs

  • Mathematica
    Select[Table[n^2, {n, 6760}], Union[Last[Transpose[Tally[IntegerDigits[#]]]]] == {2} &] (* Jayanta Basu, Jun 17 2013 *)
  • Python
    from itertools import islice
    from collections import Counter
    def afull(): yield from (x**2 for x in range(10**10) if set(Counter(str(x**2)).values()) == {2})
    print(list(islice(afull(), 47))) # Michael S. Branicky, May 12 2023

A052052 Cubes whose digits occur with an equal minimal frequency of 2.

Original entry on oeis.org

1331, 238328, 27818127, 700227072, 2815166528, 4861163384, 8972978552, 107510668875, 157376536199, 236143627741, 246963938824, 267463420307, 748118742552, 834034807997, 915215787829, 10809986553631, 11882007579259
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Examples

			888^3 = 700227072 and digits 0,2 and 7 each occur thrice.
		

Crossrefs

Extensions

Offset corrected by Michel Marcus, Aug 12 2015

A052047 Numbers k such that the digits of k^3 occur with the same frequency.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 13, 16, 17, 18, 19, 21, 22, 24, 27, 29, 32, 35, 38, 41, 59, 62, 66, 69, 73, 75, 76, 84, 88, 93, 97, 135, 145, 203, 289, 297, 302, 303, 319, 888, 1412, 1694, 2078, 4755, 5399, 6181, 6274, 6443, 9078, 9413, 9709, 22111, 22819
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Crossrefs

Programs

  • Maple
    filter:= proc(n) local L,V,k;
      L:= convert(n^3,base,10);
      V:= {seq(numboccur(k,L),k=0..9)};
      nops(V minus {0}) = 1
    end proc:filter(0):= true:select(filter, [$0..10000]); # Robert Israel, Mar 12 2020
  • Mathematica
    t={}; Do[If[Length[DeleteDuplicates[Transpose[Tally[IntegerDigits[n^3]]][[2]]]]==1,AppendTo[t,n]],{n,0,23000}]; t (* Jayanta Basu, May 11 2013 *)
    Select[Range[0,23000],Length[Union[DeleteCases[DigitCount[#^3],0]]]==1&] (* Harvey P. Dale, Jun 14 2020 *)

A052048 Cubes whose digits occur with the same frequency.

Original entry on oeis.org

0, 1, 8, 27, 64, 125, 216, 512, 729, 1331, 1728, 2197, 4096, 4913, 5832, 6859, 9261, 10648, 13824, 19683, 24389, 32768, 42875, 54872, 68921, 205379, 238328, 287496, 328509, 389017, 421875, 438976, 592704, 681472, 804357, 912673, 2460375, 3048625
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Examples

			E.g., 238328 = 62^3 -> digits 2, 3 and 8 occur each twice.
		

Crossrefs

Programs

  • Maple
    isA052048 := proc(n) local d,k,fr,eqfr: if(n=0)then return true: fi: d:=convert(n^3,base,10): eqfr:=true: fr:=numboccur(d[1],d): for k from 0 to 9 do if(not member(numboccur(k,d),{fr,0}))then eqfr:=false: break: fi: od: return eqfr: end: seq(`if`(isA052048(n), n^3, NULL), n=0..200); # Nathaniel Johnston, May 31 2011
  • Mathematica
    t={}; Do[If[Length[DeleteDuplicates[Transpose[Tally[IntegerDigits[n^3]]][[2]]]]==1,AppendTo[t,n^3]],{n,0,200}]; t (* Jayanta Basu, May 11 2013 *)

Formula

a(n) = A052047(n)^3. - Andrew Howroyd, Aug 11 2024

Extensions

Offset corrected by Andrew Howroyd, Aug 11 2024

A052051 Numbers k such that k^3 is a cube whose digits occur with an equal minimum frequency of 2.

Original entry on oeis.org

11, 62, 303, 888, 1412, 1694, 2078, 4755, 5399, 6181, 6274, 6443, 9078, 9413, 9709, 22111, 22819, 23894, 24835, 26636, 26881, 28895, 29631, 30593, 32069, 32687, 32723, 32887, 34699, 35042, 36536, 36705, 36869, 37568, 40675, 41538, 41674
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1999

Keywords

Crossrefs

A052069 a(n)^2 is the smallest square whose digits occur with the same frequency n.

Original entry on oeis.org

0, 88, 10011, 31646191, 16431563, 667567716, 10715008859, 652246443112, 15647628653832, 781035313645040
Offset: 1

Views

Author

Patrick De Geest, Jan 15 2000

Keywords

Examples

			31646191^2 = 1001481404808481 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++];
    i, {n, 10}] (* Robert Price, Oct 12 2019 *)

Extensions

2 more terms from Jon E. Schoenfield, Aug 18 2007
a(10) from Giovanni Resta, Aug 19 2018

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

A378492 Squares where larger digits have larger multiplicity.

Original entry on oeis.org

0, 1, 4, 9, 144, 441, 1444, 29929, 55225, 166464, 255025, 299209, 633616, 646416, 767376, 4999696, 9696996, 34433424, 228281881, 414041104, 414488881, 424442404, 536663556, 969699600, 1649496996, 1929229929, 2636206336, 2666999449, 2929299129, 2996029696, 4664343616
Offset: 1

Views

Author

Erich Friedman, Nov 28 2024

Keywords

Crossrefs

Programs

  • Maple
    filter:= proc(n) local L,S;
       L:= convert(n,base,10);
       S:= Statistics:-Tally(L,output=list);
       S:= sort(S, (a,b) -> lhs(a) < lhs(b));
       andmap(t -> rhs(S[t])Robert Israel, Nov 29 2024
  • Mathematica
    increasingQ[L_]:=Min[Rest[(L-RotateRight[L])]]>0;
    sortedQ[n_]:=increasingQ[Sort[Tally[IntegerDigits[n]]][[All,2]]]
    Select[Range[575000000]^2,sortedQ]
Showing 1-10 of 12 results. Next