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 10 results.

A095050 Numbers such that all ten digits are needed to write all positive divisors in decimal representation.

Original entry on oeis.org

108, 216, 270, 304, 306, 312, 324, 360, 380, 406, 432, 450, 504, 540, 570, 608, 612, 624, 630, 648, 654, 702, 708, 714, 720, 728, 756, 760, 780, 810, 812, 864, 870, 900, 910, 912, 918, 924, 936, 945, 954, 972, 980, 1008, 1014, 1026, 1032, 1036, 1038
Offset: 1

Views

Author

Reinhard Zumkeller, May 28 2004

Keywords

Comments

A095048(a(n)) = 10.
Numbers n such that A037278(n), A176558(n) and A243360(n) contain 10 distinct digits. - Jaroslav Krizek, Jun 19 2014
Once a number is in the sequence, then all its multiples will be there too. The list of primitive terms begin: 108, 270, 304, 306, 312, 360, 380, ... - Michel Marcus, Jun 20 2014
Pandigital numbers A050278 and A171102 are subsequences. - Michel Marcus, May 01 2020

Examples

			Divisors of 108 are: [1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108] where all digits can be found.
		

Crossrefs

Cf. A095048, A059436 (subsequence), A206159.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).
Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050. - Jaroslav Krizek, Jun 19 2014

Programs

  • Haskell
    import Data.List (elemIndices)
    a095050 n = a095050_list !! (n-1)
    a095050_list = map (+ 1) $ elemIndices 10 $ map a095048 [1..]
    -- Reinhard Zumkeller, Feb 05 2012
    
  • Maple
    q:= n-> is({$0..9}=map(x-> convert(x, base, 10)[], numtheory[divisors](n))):
    select(q, [$1..2000])[];  # Alois P. Heinz, Oct 28 2021
  • Mathematica
    Select[Range@2000, 1+Union@@IntegerDigits@Divisors@# == Range@10 &] (* Hans Rudolf Widmer, Oct 28 2021 *)
  • PARI
    isok(m)=my(d=divisors(m), v=[1]); for (k=2, #d, v = Set(concat(v, digits(d[k]))); if (#v == 10, return (1));); #v == 10; \\ Michel Marcus, May 01 2020
    
  • Python
    from sympy import divisors
    def ok(n):
        digits_used = set()
        for d in divisors(n):
            digits_used |= set(str(d))
        return len(digits_used) == 10
    print([k for k in range(1040) if ok(k)]) # Michael S. Branicky, Oct 28 2021

Formula

a(n) ~ n. - Charles R Greathouse IV, Nov 16 2022

A243534 Numbers n such that the list of all divisors of n contains only 1 distinct digit (in base 10).

Original entry on oeis.org

1, 11, 1111111111111111111, 11111111111111111111111
Offset: 1

Views

Author

Jaroslav Krizek, Jun 13 2014

Keywords

Comments

Union of 1 and A004022 (prime repunits).
The next term has 317 digits.
Numbers n such that A037278(n), A176558(n) and A243360(n) contain only 1 distinct digit.

Examples

			11 is in sequence because the list of the divisors of 11: (1, 11) contains only 1 distinct digit.
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543.

Programs

  • Excel
    [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=1;A(n)); Arrangement of column B]

Formula

a(1) = 1; for n >= 2, a(n+1) = A004022 (prime repunits).

A243535 Numbers whose list of divisors contains 2 distinct digits (in base 10).

Original entry on oeis.org

2, 3, 5, 7, 13, 17, 19, 22, 31, 33, 41, 55, 61, 71, 77, 101, 113, 121, 131, 151, 181, 191, 199, 211, 311, 313, 331, 661, 811, 881, 911, 919, 991, 1111, 1117, 1151, 1171, 1181, 1511, 1777, 1811, 1999, 2111, 2221, 3313, 3331, 4111, 4441, 6661, 7177, 7717, 8111
Offset: 1

Views

Author

Jaroslav Krizek, Jun 13 2014

Keywords

Comments

Numbers k such that A037278(k), A176558(k) and A243360(k) contain 2 distinct digits.
Many of the composite terms are in A203897. - Charles R Greathouse IV, Sep 06 2016
Terms are either repdigit numbers (A010785) or contain only 1 and a single other digit. - Michael S. Branicky, Nov 16 2022

Examples

			121 is in the sequence because the list of divisors of 121, i.e., (1, 11, 121), contains 2 distinct digits (1, 2).
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1..10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=2;A(n)); Arrangement of column B]
    
  • Maple
    dmax:= 6: # get all terms of <= dmax digits
    Res:= {}:
    for a in [0,$2..9] do
        S:= {0}:
        for d from 1 to dmax do
            S:= map(t -> (10*t+1,10*t+a), S);
            Res:= Res union select(filter, S)
        od
    od:
    sort(convert(Res,list)): # Robert Israel, Sep 05 2016
  • Mathematica
    Select[Range[9000],Length[Union[Flatten[IntegerDigits/@Divisors[ #]]]] == 2&] (* Harvey P. Dale, Dec 14 2017 *)
  • PARI
    isok(n) = vd = []; fordiv(n, d, vd = concat(vd, digits(d))); #Set(vd) == 2; \\ Michel Marcus, Jun 13 2014
    
  • Python
    from sympy import divisors
    from itertools import count, islice, product
    def ok(n):
        s = set("1"+str(n))
        if len(s) > 2: return False
        for d in divisors(n, generator=True):
            s |= set(str(d))
            if len(s) > 2: return False
        return len(s) == 2
    def agen():
        yield from [2, 3, 5, 7]
        for d in count(2):
            s = set()
            for first, other in product("123456789", "0123456789"):
                for p in product(sorted(set(first+other)), repeat=d-1):
                    if other not in p: continue
                    t = int(first+"".join(p))
                    if ok(t): s.add(t)
            yield from sorted(s)
    print(list(islice(agen(), 52))) # Michael S. Branicky, Nov 16 2022

A243536 Numbers n such that list of divisors of n contains 3 distinct digits (in base 10).

Original entry on oeis.org

4, 9, 15, 23, 25, 29, 37, 39, 43, 44, 47, 53, 59, 67, 73, 79, 83, 89, 93, 95, 97, 99, 103, 107, 109, 111, 119, 122, 125, 127, 137, 139, 143, 149, 155, 157, 163, 167, 173, 179, 187, 193, 197, 202, 223, 227, 229, 233, 241, 242, 251, 271, 277, 281, 303, 317, 337
Offset: 1

Views

Author

Jaroslav Krizek, Jun 13 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 3 distinct digits.

Examples

			44 is in sequence because list of divisors of 44: (1, 2, 4, 11, 22, 44) contains 3 distinct digits (1, 2, 4).
		

Crossrefs

Sequences of numbers n such that list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=3;A(n)); Arrangement of column B]

A243537 Numbers n such that list of divisors of n contains 4 distinct digits (in base 10).

Original entry on oeis.org

6, 8, 10, 14, 21, 26, 35, 49, 50, 51, 62, 65, 66, 82, 85, 88, 91, 110, 115, 117, 123, 133, 141, 142, 159, 165, 169, 183, 209, 213, 217, 221, 226, 231, 239, 244, 250, 253, 257, 262, 263, 269, 275, 283, 293, 295, 299, 307, 309, 319, 326, 333, 347, 349, 355, 359
Offset: 1

Views

Author

Jaroslav Krizek, Jun 13 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 4 distinct digits.

Examples

			49 is in sequence because divisors of 49: (1, 7, 49) contain 4 distinct digits (1, 4, 7, 9).
		

Crossrefs

Sequences of numbers n such that list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543.

Programs

  • Excel
    [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=4;A(n)); Arrangement of column B]
  • Mathematica
    Select[Range[400],Length[Union[Flatten[IntegerDigits/@Divisors[#]]]] == 4&] (* Harvey P. Dale, Aug 22 2021 *)

A243538 Numbers n such that the list of divisors of n contains 5 distinct digits (in base 10).

Original entry on oeis.org

12, 16, 20, 27, 28, 34, 38, 45, 46, 57, 58, 69, 74, 75, 94, 100, 118, 124, 129, 132, 145, 153, 154, 161, 164, 166, 171, 175, 177, 178, 185, 194, 195, 205, 206, 214, 215, 218, 219, 220, 237, 254, 265, 273, 274, 279, 284, 287, 289, 291, 297, 298, 301, 302, 305
Offset: 1

Views

Author

Jaroslav Krizek, Jun 19 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 5 distinct digits.

Examples

			45 is in sequence because the list of divisors of 45: (1, 3, 5, 9, 15, 45) contains 5 distinct digits (1, 3, 4, 5, 9).
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1...10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=5;A(n)); Arrangement of column B]

A243539 Numbers n such that the list of divisors of n contains 6 distinct digits (in base 10).

Original entry on oeis.org

18, 24, 30, 32, 40, 42, 48, 52, 63, 64, 81, 86, 87, 92, 98, 105, 106, 128, 130, 134, 146, 147, 148, 158, 176, 186, 188, 198, 200, 201, 203, 222, 235, 246, 247, 248, 249, 255, 259, 264, 278, 286, 310, 314, 322, 327, 328, 329, 330, 332, 334, 338, 346, 351, 357
Offset: 1

Views

Author

Jaroslav Krizek, Jun 19 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 6 distinct digits.

Examples

			48 is in sequence because the list of divisors of 48: (1, 2, 3, 4, 6, 8, 12, 16, 24, 48) contains 6 distinct digits (1, 2, 3, 4, 6, 8).
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1...10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=6;A(n)); Arrangement of column B]
  • Mathematica
    Select[Range[400],Length[Union[Flatten[IntegerDigits/@Divisors[#]]]]==6&] (* Harvey P. Dale, Apr 13 2025 *)

A243541 Numbers n such that the list of divisors of n contains 8 distinct digits (in base 10).

Original entry on oeis.org

72, 76, 102, 104, 120, 126, 140, 144, 160, 168, 170, 182, 208, 210, 224, 232, 234, 236, 240, 258, 266, 276, 282, 288, 294, 296, 300, 308, 318, 320, 336, 352, 370, 372, 376, 416, 424, 430, 435, 436, 438, 448, 460, 464, 470, 476, 483, 494, 518, 520, 528, 536
Offset: 1

Views

Author

Jaroslav Krizek, Jun 19 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 8 distinct digits.

Examples

			72 is in sequence because the list of divisors of 72: (1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72) contains 8 distinct digits (1, 2, 3, 4, 6, 7, 8, 9).
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=8;A(n)); Arrangement of column B]
  • Mathematica
    Select[Range[600],Length[Union[Flatten[IntegerDigits/@Divisors[#]]]]==8&] (* Harvey P. Dale, Jul 14 2016 *)

A243542 Numbers n such that the list of divisors of n contains 9 distinct digits (in base 10).

Original entry on oeis.org

54, 90, 114, 152, 156, 162, 174, 180, 204, 228, 252, 280, 315, 316, 340, 342, 348, 354, 356, 364, 378, 390, 392, 405, 408, 414, 420, 456, 468, 472, 474, 480, 486, 490, 510, 516, 522, 532, 534, 546, 552, 556, 560, 564, 576, 582, 584, 588, 592, 594, 600, 616
Offset: 1

Views

Author

Jaroslav Krizek, Jun 19 2014

Keywords

Comments

Numbers n such that A037278(n), A176558(n) and A243360(n) contain 9 distinct digits.

Examples

			54 is in sequence because the list of divisors of 54: (1, 2, 3, 6, 9, 18, 27, 54) contains 9 distinct digits (1, 2, 3, 4, 5, 6, 7, 8, 9).
		

Crossrefs

Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Cf. A243543 (the smallest number m whose list of divisors contains n distinct digits).

Programs

  • Excel
    [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=9;A(n)); Arrangement of column B]

A243543 Smallest number whose list of divisors contains n distinct digits (in base 10).

Original entry on oeis.org

1, 2, 4, 6, 12, 18, 36, 72, 54, 108
Offset: 1

Views

Author

Jaroslav Krizek, Jun 19 2014

Keywords

Comments

Finite sequence with 10 terms.

Examples

			a(9) = 54 because 54 is the smallest number whose list of divisors contains 9 distinct digits; the list of divisors of 54: (1, 2, 3, 6, 9, 18, 27, 54) contains 9 distinct digits (1, 2, 3, 4, 5, 6, 7, 8, 9).
		

Crossrefs

Cf. Sequences of numbers n such that list of divisors of n contains k distinct digits: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050.
Showing 1-10 of 10 results.