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 1-9 of 9 results.

A054038 Numbers k such that k^2 contains every digit at least once.

Original entry on oeis.org

32043, 32286, 33144, 35172, 35337, 35757, 35853, 37176, 37905, 38772, 39147, 39336, 40545, 42744, 43902, 44016, 45567, 45624, 46587, 48852, 49314, 49353, 50706, 53976, 54918, 55446, 55524, 55581, 55626, 56532, 57321, 58413, 58455
Offset: 1

Views

Author

Asher Auel, Feb 28 2000

Keywords

Comments

There are 87 terms < 10^5; these are the n such that n^2 uses each digit exactly once. - David Wasserman, Feb 03 2005
The squares in this sequence are in A190682. - Bruno Berselli, May 23 2011

References

  • J.-M. De Koninck and A. Mercier, 1001 Problemes en Theorie Classique Des Nombres, Problem 239 pp. 39; 178, Ellipses Paris 2004.

Crossrefs

Programs

  • Magma
    IsA054038:=func< n | Seqset(Intseq(n^2)) eq {0,1,2,3,4,5,6,7,8,9} >; [ n: n in [1..60000] | IsA054038(n) ]; // Klaus Brockhaus, May 16 2011
    
  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=10 then f := [op(f),i] fi; od; f;
  • Mathematica
    A050278 = Select[FromDigits@#&/@Permutations[Range[0, 9], {10}], # > 10^9 &]; Sqrt[Select[A050278, IntegerQ[Sqrt[#]] &]] (* Alonso del Arte, Jun 18 2011, based on a program by Robert G. Wilson v *)
    Select[Sqrt[#]&/@FromDigits/@Select[Permutations[Range[0,9]],#[[1]]>0&], IntegerQ] (* Harvey P. Dale, May 26 2016 *)
  • PARI
    is(n)=#vecsort(Vec(Str(n^2)),,8)==10 \\ Charles R Greathouse IV, Jun 18 2011
    
  • Python
    def ok(n): return len(set(str(n**2))) == 10
    print([k for k in range(10**5) if ok(k)]) # Michael S. Branicky, Dec 23 2022

Extensions

More terms from David Wasserman, Feb 03 2005

A054037 Numbers k such that k^2 contains exactly 9 different digits.

Original entry on oeis.org

10124, 10128, 10136, 10214, 10278, 11826, 12363, 12543, 12582, 12586, 13147, 13268, 13278, 13343, 13434, 13545, 13698, 14098, 14442, 14676, 14743, 14766, 15353, 15681, 15963, 16549, 16854, 17252, 17529, 17778, 17816, 18072, 19023, 19377, 19569, 19629, 20089
Offset: 1

Views

Author

Asher Auel, Feb 28 2000

Keywords

Comments

There are three prime numbers {13147, 20089, 21397} and corresponding squares {172843609, 403567921, 457831609} necessarily contain zero (otherwise n and n^2 are divisible by 3). - Zak Seidov, Jan 18 2012

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=9 then f := [op(f),i] fi; od; f;
  • Mathematica
    okQ[n_] := Module[{n2=n^2}, Max[DigitCount[n2,10]]==1 && IntegerLength[n2]==9]; Select[Range[20000], okQ]  (* Harvey P. Dale, Mar 20 2011 *)
  • Python
    from itertools import count, islice
    def agen(): yield from (k for k in count(10**4) if len(set(str(k*k)))==9)
    print(list(islice(agen(), 37))) # Michael S. Branicky, May 24 2022

A054039 a(n)^2 is the least square to contain n different decimal digits.

Original entry on oeis.org

0, 4, 13, 32, 113, 322, 1017, 3206, 10124, 32043
Offset: 1

Views

Author

Asher Auel, Feb 28 2000

Keywords

Comments

It turns out that "...at least n..." and "...exactly n..." yield the same (and thus strictly increasing) sequence. - M. F. Hasler, Feb 02 2009

Examples

			13^2=169 is the first square to contain exactly 3 different digits; 322^2=103684 is the first square to contain exactly 6 different digits.
		

Crossrefs

Programs

  • PARI
    A054039(n,k=0) = { while( #Set(Vec(Str(k^2)))M. F. Hasler, Feb 02 2009 */

Extensions

Minor rewording, added comment, keywords "easy,full" and PARI code M. F. Hasler, Feb 02 2009

A054032 Numbers n such that n^2 contains exactly 4 different digits.

Original entry on oeis.org

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, 89, 93, 95, 96, 98, 99, 103, 104, 105, 106, 112, 114, 115, 123, 125, 127, 130, 132, 135, 138, 139, 140, 143, 145, 146, 151, 155, 156, 157, 158
Offset: 1

Views

Author

Asher Auel, Feb 29 2000

Keywords

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=4 then f := [op(f),i] fi; od; f;
  • Mathematica
    t = {}; n = -1; While[Length[t] < 50, n++; If[Length[Union[IntegerDigits[n^2]]] == 4, AppendTo[t, n]]] (* T. D. Noe, Apr 26 2013 *)
  • PARI
    is(n)=#Set(digits(n^2))==4 \\ Charles R Greathouse IV, Feb 11 2017

A054033 Numbers n such that n^2 contains exactly 5 different digits.

Original entry on oeis.org

113, 116, 117, 118, 124, 126, 128, 133, 134, 136, 137, 142, 144, 147, 148, 152, 153, 154, 169, 172, 174, 175, 176, 178, 179, 181, 186, 189, 191, 193, 195, 196, 198, 199, 203, 209, 213, 214, 217, 219, 224, 226, 228, 232, 233, 248, 252, 259, 267, 268, 269
Offset: 1

Views

Author

Asher Auel, Feb 29 2000

Keywords

Comments

The first 66 terms are the only ones whose squares contain no repeated digits. - Charles R Greathouse IV, Feb 09 2015

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=5 then f := [op(f),i] fi; od; f;
  • Mathematica
    Select[Range[101,500],Count[DigitCount[#^2],0]==5&] (* Harvey P. Dale, Feb 08 2015 *)
  • PARI
    is(n)=#Set(digits(n^2))==5 \\ Charles R Greathouse IV, Feb 08 2015

A054034 Numbers n such that n^2 contains exactly 6 different digits.

Original entry on oeis.org

322, 323, 324, 328, 352, 353, 364, 367, 374, 375, 397, 403, 405, 413, 416, 425, 442, 445, 456, 458, 463, 487, 504, 507, 508, 509, 529, 542, 557, 564, 567, 571, 572, 574, 584, 589, 591, 593, 597, 598, 616, 618, 621, 625, 626, 629, 634, 637, 639, 645, 647
Offset: 1

Views

Author

Asher Auel, Feb 29 2000

Keywords

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=6 then f := [op(f),i] fi; od; f;
  • Mathematica
    Select[Range[700],Count[DigitCount[#^2],0]==4&] (* Harvey P. Dale, May 10 2021 *)

A054035 Numbers n such that n^2 contains exactly 7 different digits.

Original entry on oeis.org

1017, 1023, 1024, 1027, 1028, 1036, 1037, 1042, 1113, 1117, 1164, 1175, 1176, 1197, 1228, 1267, 1268, 1277, 1302, 1307, 1323, 1328, 1343, 1352, 1355, 1375, 1395, 1405, 1428, 1433, 1441, 1442, 1444, 1463, 1541, 1593, 1594, 1628, 1646, 1648, 1701, 1706
Offset: 1

Views

Author

Asher Auel, Feb 29 2000

Keywords

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=7 then f := [op(f),i] fi; od; f;
  • Mathematica
    Select[Range[2000],Count[DigitCount[#^2],0]==3&] (* Harvey P. Dale, Jul 28 2012 *)

A054036 Numbers n such that n^2 contains exactly 8 different digits.

Original entry on oeis.org

3206, 3267, 3268, 3292, 3674, 3678, 3698, 3723, 3734, 4047, 4097, 4157, 4175, 4455, 4537, 4554, 4616, 4634, 4663, 4804, 4814, 4896, 4913, 4967, 4987, 5376, 5529, 5699, 5742, 5853, 5899, 5904, 5905, 5968, 6043, 6071, 6095, 6098, 6127, 6176, 6181, 6199
Offset: 1

Views

Author

Asher Auel, Feb 28 2000

Keywords

Examples

			3206 is in the sequence because 3206^2 = 10278436 and 10278436 contains exactly eight different digits: 0, 1, 2, 3, 4, 6, 7 and 8.
		

Crossrefs

Programs

  • Maple
    f := []; for i from 0 to 200 do if nops({op(convert(i^2,base,10))})=8 then f := [op(f),i] fi; od; f;
  • Mathematica
    Select[Range[7000],Count[DigitCount[#^2],0]==2&] (* Harvey P. Dale, Aug 10 2017 *)

A235718 Squares which have one or more occurrences of exactly three different digits.

Original entry on oeis.org

169, 196, 256, 289, 324, 361, 529, 576, 625, 729, 784, 841, 961, 1156, 1225, 1521, 1600, 1681, 2025, 2116, 2209, 2500, 3136, 3364, 3600, 3844, 3969, 4225, 4489, 4624, 4900, 5625, 5776, 5929, 6400, 6561, 6889, 7225, 8100, 8281, 8464, 8836, 9409, 10201, 10404
Offset: 1

Views

Author

Colin Barker, Jan 15 2014

Keywords

Comments

The first term having a repeated digit is 1156.

Examples

			5929 is in the sequence because 5929 = 77^2 and 5929 contains exactly three different digits: 2, 5 and 9.
		

Crossrefs

Programs

  • PARI
    s=[]; for(n=1, 200, if(#vecsort(eval(Vec(Str(n^2))),,8)==3, s=concat(s, n^2))); s

Formula

a(n) = A054031(n)^2.
Showing 1-9 of 9 results.