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 20 results. Next

A032533 Numbers that, when expressed in base 2 and then interpreted in base 10, yield a multiple of the original number.

Original entry on oeis.org

1, 2, 4, 8, 10, 16, 20, 21, 32, 40, 42, 64, 80, 84, 100, 128, 160, 168, 200, 256, 273, 320, 336, 400, 512, 546, 640, 672, 800, 1000, 1024, 1092, 1280, 1344, 1600, 2000, 2048, 2184, 2231, 2510, 2560, 2688, 2730, 3200, 3300, 4000, 4096, 4368, 4462
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Comments

Note that A025612 is a subset of this sequence (numbers of form 2^i*10^j, with i, j >= 0).

Examples

			8 in base 2 is 1000, which interpreted in base 10 is 1000 = 125*8.
		

Crossrefs

Programs

  • Magma
    [k:k in [1..5000]| Seqint(Intseq(k,2)) mod k eq 0]; // Marius A. Burtea, Oct 11 2019
    
  • Mathematica
    Select[Range[10000], Mod[FromDigits[IntegerDigits[#, 2]], #] == 0 &] (* Carl Najafi, Aug 18 2011 *)
  • PARI
    select( is_A032533(n)=fromdigits(binary(n))%n==0, [1..5000]) \\ M. F. Hasler, Oct 11 2019

Formula

A032533 = { m : m divides A007088(m) }. - M. F. Hasler, Oct 11 2019

Extensions

Example and better description from Erich Friedman, Jul 21 2001
Edited by Erich Friedman, Feb 09 2002
Offset set to 1 by Giovanni Resta, Jul 13 2016
Name edited by Jon E. Schoenfield, Oct 25 2019

A032549 Numbers that, when expressed in base 7 and then interpreted in base 10, yield a multiple of the original number.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 51, 102, 105, 153, 156, 207, 210, 258, 261, 312, 315, 2589, 2590, 2601, 2753, 5354, 5355, 5506, 8108, 8259, 8260, 10861, 11013, 11025, 13614, 13615, 13626, 13766, 13778, 16379, 16380, 16531, 33045, 140403, 289065, 1123224
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Comments

Decimal 'base-7 looking' numbers divided by their actual base-7 values (n) is an integer.

Crossrefs

Cf. A032548, A032550. See also A032532 for explanation.

Programs

  • Mathematica
    Select[Range@ 300000, Mod[ FromDigits[ IntegerDigits[#, 7]], #] == 0 &] (* Giovanni Resta, Oct 21 2019 *)

Extensions

Offset set to 1 by Giovanni Resta, Oct 21 2019
Name edited by Jon E. Schoenfield, Oct 25 2019

A032540 Numbers that, when expressed in base 4 and then interpreted in base 10, yield a multiple of the original number.

Original entry on oeis.org

0, 1, 2, 3, 6, 24, 120, 171, 177, 273, 362, 440, 546, 819, 1418, 1560, 1582, 1638, 1760, 1806, 2400, 2841, 2927, 3640, 4706, 4882, 5720, 6328, 6552, 7040, 7224, 9431, 9600, 10101, 14560, 20202, 22880, 24800, 25080, 25312, 28896, 32760, 36974, 38400
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Comments

n such that A007090(n) is a multiple of n. - Robert Israel, Sep 13 2018

Examples

			24 in base 4 is 120, which interpreted in base 10 is 120 = 5*24.
		

Crossrefs

Programs

  • Maple
    filter:= proc(n) local L,t;
      L:= convert(n,base,4);
      t:= add(L[i]*10^(i-1),i=1..nops(L));
      t mod n = 0
    end proc:
    filter(0):=true:
    select(filter, [$0..10^5]); # Robert Israel, Sep 13 2018
  • Mathematica
    Join[{0}, Select[Range[40000], Divisible[FromDigits[IntegerDigits[#,4]], #]&]]  (* Harvey P. Dale, Apr 20 2011 *)

Extensions

More terms from Erich Friedman and Naohiro Nomoto, Aug 06 2001
Offset changed by Robert Israel, Sep 13 2018
Name edited by Jon E. Schoenfield, Oct 25 2019

A032551 Numbers that, when expressed in base 8 and then interpreted in base 10, yield a multiple of the original number.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 34217, 34354, 68582, 68719, 68720, 70525, 70537, 70674, 104891, 104902, 105039, 105040, 106845, 139257, 141211, 141348, 175577, 175714, 177519, 177520, 177668, 211885, 212022, 212034, 213839, 213840, 248205, 248342, 250148
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Comments

Decimal 'base-8 looking' numbers divided by their actual base-8 value is an integer.
There are only 37 terms up to 30 million. - Harvey P. Dale, Sep 29 2012

Examples

			7 in base 8 is 7, which interpreted in base 10 is 7=1*7.
		

Crossrefs

Cf. A032552. See also A032532.

Programs

  • Mathematica
    Join[{0},Select[Range[300000],Divisible[FromDigits[ IntegerDigits[ #,8]],#]&]] (* Harvey P. Dale, Sep 29 2012 *)

Extensions

Edited by N. J. A. Sloane, Jun 07 2008 at the suggestion of Sergio Pimentel
Name edited by Jon E. Schoenfield, Oct 25 2019

A032538 Quotient of 'base-3' division described in A032537.

Original entry on oeis.org

1, 1, 3, 8, 8, 10, 29, 111, 85, 111, 104, 101, 370, 286, 286, 370, 333, 1105, 888, 1312, 1219, 1110, 1115, 3737, 3634, 3303, 2960, 3700, 14853, 14232, 11010, 49510, 47440, 44444, 36700, 45211, 42815, 147741, 112398, 108115, 154789, 492470
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Crossrefs

Cf. A032536, A032537. See also A032532 for explanation.

Programs

  • Mathematica
    Select[ FromDigits@ IntegerDigits[#, 3] / # & /@ Range[10^5], IntegerQ] (* Giovanni Resta, Jul 13 2016 *)

Extensions

Offset set to 1 by Giovanni Resta, Jul 13 2016

A032545 Integer part of decimal 'base-6 looking' numbers divided by their actual base-6 values, rounded down.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Crossrefs

See also A032532 for explanation.

Programs

  • Mathematica
    Array[IntegerPart[FromDigits[#2]/#1] & @@ {#, IntegerDigits[#, 6]} &, 105] (* Michael De Vlieger, Oct 06 2019 *)
  • PARI
    for(n=1,1e3,v=eval(Vec(Str(n)));if(vecmax(v)<6, print1(n\sum(i=1,#v,v[i]*6^(#v-i))", "))) \\ Charles R Greathouse IV, Apr 08 2012

Formula

a(n) = floor(A007092(n)/n). - Sean A. Irvine, Jun 22 2020

A032546 Numbers that, when expressed in base 6 and then interpreted in base 10, yield a multiple of the original number.

Original entry on oeis.org

1, 2, 3, 4, 5, 308, 4920, 11284, 11914, 144393, 195453, 518659, 866358, 925148, 1010765, 1172718, 1369865, 2141968, 2557924, 4287428, 4296908, 6064590, 8219190, 15347544, 16891738, 18409156, 18532263, 21880744, 23693054
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Comments

Original name: Decimal 'base 6 looking' numbers divided by their actual base 6 values (n) is an integer.

Examples

			308 is a term: 308_10 = 1232_6; 1232 = 308*4. - _Jon E. Schoenfield_, Oct 25 2019
		

Crossrefs

Cf. A032545, A032547. See also A032532 for explanation.

Extensions

Offset changed and Name edited by Jon E. Schoenfield, Oct 25 2019

A032548 Integer part of decimal 'base-7 looking' numbers divided by their actual base-7 values.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Crossrefs

Cf. A007093, A032549, A032550. See also A032532 for explanation.

Programs

Formula

a(n) = floor(A007093(n)/n). - Antti Karttunen, Jan 01 2019

Extensions

Offset corrected by Antti Karttunen, Jan 01 2019

A032534 Quotient of 'base-2' division described in A032533.

Original entry on oeis.org

1, 5, 25, 125, 101, 625, 505, 481, 3125, 2525, 2405, 15625, 12625, 12025, 11001, 78125, 63125, 60125, 55005, 390625, 366337, 315625, 300625, 275025, 1953125, 1831685, 1578125, 1503125, 1375125, 1111101, 9765625, 9158425, 7890625
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Crossrefs

Programs

  • Mathematica
    Array[If[Mod[#2, #1] == 0, #2/#1, Nothing] & @@ {#, FromDigits[IntegerDigits[#, 2]]} &, 10^3] (* Michael De Vlieger, Oct 06 2019 *)

Extensions

Offset 1 from Michael De Vlieger, Oct 06 2019

A032536 Integer part of decimal 'base-3 looking' numbers divided by their actual base-3 values.

Original entry on oeis.org

1, 1, 3, 2, 2, 3, 3, 2, 11, 10, 9, 9, 8, 8, 8, 7, 7, 11, 10, 10, 10, 9, 9, 9, 8, 8, 37, 35, 34, 33, 32, 31, 30, 30, 29, 30, 29, 29, 28, 27, 27, 26, 26, 25, 26, 26, 25, 25, 24, 24, 23, 23, 23, 37, 36, 35, 35, 34, 34, 33, 33, 32, 33, 32, 32, 31, 31, 31, 30, 30, 29, 30, 30
Offset: 1

Views

Author

Patrick De Geest, Apr 15 1998

Keywords

Crossrefs

Cf. A007089, A032537, A032538. See also A032532 for explanation.

Programs

  • Mathematica
    Quotient[ FromDigits /@ IntegerDigits[ Range@ 73, 3], Range@ 73] (* Giovanni Resta, Jul 12 2016 *)

Formula

a(n) = floor(A007089(n)/n).

Extensions

Offset corrected by Giovanni Resta, Jul 12 2016
Showing 1-10 of 20 results. Next