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 13 results. Next

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

A156977 Numbers n such that n^2 contains every decimal digit exactly 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, 58554, 59403, 60984
Offset: 1

Views

Author

Zak Seidov, Feb 20 2009

Keywords

Comments

There are exactly 87 such numbers, none of them being prime.
Since 0 + 1 +...+ 9 = 5*9, every pandigital number is divisible by 9, hence every term of this sequence is divisible by 3 and so cannot be a prime. - Giovanni Resta, Mar 19 2013 [Comment expanded by N. J. A. Sloane, Jan 15 2022]

Crossrefs

Programs

  • Magma
    [n: n in [Floor(Sqrt(1023456789))..Ceiling(Sqrt(9876543210))] | Set(Intseq(n^2)) eq {0..9}]; // Bruno Berselli, Mar 19 2013 (after Giovanni Resta)
  • Maple
    lim:=floor(sqrt(9876543210)): for n from floor(sqrt(1023456789)) to lim do d:=[op(convert(n^2, base, 10))]: pandig:=true: for k from 0 to 9 do if(numboccur(k, d)<>1)then pandig:=false: break: fi: od: if(pandig)then printf("%d, ",n): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    Select[Range[Floor@Sqrt@1023456789, Ceiling@Sqrt@9876543210], Sort@IntegerDigits[#^2] == Range[0, 9] &] (* Giovanni Resta, Mar 19 2013 *)
    Select[Range[31992,99381,3],Union[DigitCount[#^2]]=={1}&] (* Harvey P. Dale, Jan 17 2022 *)

Formula

a(n) = sqrt(A036745(n)).

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

A071519 Numbers whose square is a zeroless pandigital number (i.e., use the digits 1 through 9 once).

Original entry on oeis.org

11826, 12363, 12543, 14676, 15681, 15963, 18072, 19023, 19377, 19569, 19629, 20316, 22887, 23019, 23178, 23439, 24237, 24276, 24441, 24807, 25059, 25572, 25941, 26409, 26733, 27129, 27273, 29034, 29106, 30384
Offset: 1

Views

Author

Lekraj Beedassy, Jun 20 2002

Keywords

Crossrefs

A subset of A054037.

Programs

  • Maple
    lim:=floor(sqrt(987654321)): for n from floor(sqrt(123456789)) to lim do d:=[op(convert(n^2, base, 10))]: pandig:=true: for k from 1 to 9 do if(numboccur(k, d)<>1)then pandig:=false: break: fi: od: if(pandig)then printf("%d, ", n): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    Sqrt[#]&/@Select[FromDigits/@Permutations[Range[9]],IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Sep 23 2011 *)
    Select[Range[11112, 31427,3], DigitCount[#^2] == {1,1,1,1,1,1,1,1,1,0} &]  (* Zak Seidov, Jan 11 2012 *)
  • PARI
    A071519 = select( {is_A071519(n,L=[1..9])=vecsort(digits(n^2))==L}, [1e5\9..1e5\3]) \\ M. F. Hasler, Jun 28 2023

Formula

a(n) = sqrt(A036744(n)). - Zak Seidov, Jan 11 2012

A054031 Numbers whose square contains exactly 3 distinct digits.

Original entry on oeis.org

13, 14, 16, 17, 18, 19, 23, 24, 25, 27, 28, 29, 31, 34, 35, 39, 40, 41, 45, 46, 47, 50, 56, 58, 60, 62, 63, 65, 67, 68, 70, 75, 76, 77, 80, 81, 83, 85, 90, 91, 92, 94, 97, 101, 102, 107, 108, 110, 111, 119, 120, 121, 122, 129, 131, 141, 149, 150, 162, 165
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))})=3 then f := [op(f),i] fi; od; f;
  • Mathematica
    t = {}; n = -1; While[Length[t] < 50, n++; If[Length[Union[IntegerDigits[n^2]]] == 3, AppendTo[t, n]]] (* T. D. Noe, Apr 26 2013 *)
    Select[Range[200],Length[Union[IntegerDigits[#^2]]]==3&] (* Harvey P. Dale, Aug 17 2014 *)
  • PARI
    is(n)=#Set(digits(n^2))==3 \\ Charles R Greathouse IV, Feb 11 2017

Formula

A235718(n) = a(n)^2. - Giovanni Resta, Apr 28 2017

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 *)
Showing 1-10 of 13 results. Next