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 1-7 of 7 results.

A241142 Numbers n such that n and 6n share at least one digit.

Original entry on oeis.org

2, 4, 6, 8, 10, 12, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 34, 36, 38, 39, 40, 41, 42, 44, 46, 48, 49, 50, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 66, 68, 70, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86, 88, 90, 92, 94, 95, 96, 98, 99, 100
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Comments

All numbers n which are congruent to 0 (mod 6) have this characteristic.
All even n have this characteristic, because n == 6n mod 10. Robert Israel, Apr 17 2014

Examples

			12 is in the sequence since 12 and 6*12 = 72 and together they share the digit 2.
		

Crossrefs

Programs

  • Maple
      N:= 10000;  # to get all entries up to N
    filter:= proc(n) local L, L6;
       L:= convert(convert(n,base,10),set);
       L6:= convert(convert(6*n,base,10),set);
       L intersect L6 <> {};
    end;
    select(filter, [$1..N]); # Robert Israel, Apr 17 2014
  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[6 n]] != {}; Select[ Range[ 100], fQ]
  • PARI
    isok(n) = #setintersect(Set(digits(n)), Set(digits(6*n))); \\ Michel Marcus, Apr 17 2014

A241141 Numbers n such that n and 5n share at least one digit.

Original entry on oeis.org

5, 10, 15, 19, 20, 21, 24, 25, 30, 31, 35, 39, 40, 42, 45, 48, 49, 50, 51, 52, 53, 55, 57, 59, 60, 63, 65, 70, 73, 74, 75, 79, 80, 84, 85, 90, 94, 95, 98, 99, 100, 101, 102, 103, 104, 105, 106, 108, 110, 115, 119, 120, 122, 123, 124, 125, 126, 130, 135, 136, 139, 140, 142, 143, 145, 147, 148, 149, 150, 151, 153
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Comments

All numbers n which are congruent to 0 (mod 5) have this characteristic.

Examples

			19 is in the sequence since 19 and 5*19 = 95 and together they share the digit 9.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[5 n]] != {} && Mod[n, 5] != 0; Select[ Range[ 100], fQ]
  • PARI
    isok(n) = #setintersect(Set(digits(n)), Set(digits(5*n))); \\ Michel Marcus, Apr 17 2014

A241143 Numbers n such that n and 7n share at least one digit.

Original entry on oeis.org

5, 10, 13, 15, 16, 17, 18, 19, 20, 21, 25, 26, 29, 30, 31, 32, 33, 34, 35, 39, 40, 42, 43, 45, 49, 50, 51, 53, 55, 60, 64, 65, 66, 67, 68, 70, 71, 75, 80, 83, 84, 85, 86, 90, 95, 96, 97, 98, 99, 100, 101, 102, 103, 105, 107, 110, 113, 115, 116, 117, 118, 120, 123, 125, 126, 128, 129, 130, 131, 132, 133, 134, 135, 139, 140
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Comments

All numbers n which are congruent to 0 (mod 5) have this characteristic.

Examples

			13 is in the sequence since 13 and 7*13 = 91 and together they share the digit 1.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[7 n]] != {}; Select[ Range[ 100], fQ]

A241144 Numbers n such that n and 8n share at least one digit.

Original entry on oeis.org

10, 13, 14, 15, 16, 17, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30, 32, 38, 39, 40, 43, 46, 47, 48, 49, 50, 54, 57, 60, 62, 65, 67, 70, 72, 76, 80, 81, 85, 86, 90, 96, 97, 98, 99, 100, 101, 102, 105, 108, 110, 114, 119, 120, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Examples

			13 is in the sequence since 13 and 8*13 = 104 and together they share the digit 1.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[8 n]] != {}; Select[ Range[ 140], fQ]

A241145 Numbers n such that n and 9n share at least one digit.

Original entry on oeis.org

5, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 32, 34, 35, 36, 37, 38, 39, 40, 43, 45, 46, 47, 48, 49, 50, 51, 54, 55, 56, 57, 58, 59, 60, 63, 64, 65, 67, 68, 69, 70, 73, 75, 76, 78, 79, 80, 82, 85, 87, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 105, 109, 110, 112, 113
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Examples

			13 is in the sequence since 13 and 8*13 = 104 and together they share the digit 1.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Intersection[ IntegerDigits[ n], IntegerDigits[9 n]] != {}; Select[ Range[ 115], fQ]

A241146 Least number k such that k and n*k share at least one digit.

Original entry on oeis.org

1, 10, 5, 10, 5, 2, 5, 10, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 1, 9, 5, 10, 5, 2, 5, 6, 5, 5, 1, 10, 5, 10, 4, 2, 4, 10, 5, 10, 1, 10, 5, 3, 3, 2, 5, 8, 5, 5, 1, 10, 5, 7, 5, 2, 5, 10, 5, 2, 1, 2, 2, 2, 5, 2, 5, 7, 5, 5, 1, 10, 5, 10, 5, 2, 3, 3, 3, 10, 1, 7, 5, 10, 4, 2, 4, 9, 5, 5, 1, 10, 5, 6, 5, 2, 5, 8, 5, 1
Offset: 1

Views

Author

Robert G. Wilson v, Apr 16 2014

Keywords

Comments

\ 10^3...10^4....10^5.....10^6......10^7.......10^8........10^9
k\
.1..272...3440...40952...468560...5217032...56953280...612579512
.2..149...1613...16837...171325...1710773...16837421...163825573
.3...87...1091...12038...124060...1225493...11762254...110573419
.4...62....710....7196....68280....621670....5502346....47710882
.5..248...1914...14674...111846....848318....6407338....48220222
.6...26....246....2087....16749....129768.....980911.....7280424
.7...36....323....2587....19368....138838.....966609.....6591845
.8...20....156....1095.....7199.....45386.....277985.....1667513
.9...22....162....1028.....6055.....34178.....187661.....1010240
10...78....345....1506.....6558.....28544.....124195......540370
The sequence of numbers whose first digit is k:
.1: 1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 31, 41, 51, 61, 71, 81, 91, 100, …, . A011531?
.2: 6, 26, 36, 46, 56, 60, 62, 63, 64, 66, 76, 86, 96, 206, 226, 236, 246, 256, 260, 262, …, .
.3: 44, 45, 77, 78, 79, 244, 245, 277, 278, 279, 344, 345, 377, 378, 379, 434, 435, 437, 438, …, .
.4: 35, 37, 85, 87, 235, 237, 285, 287, 335, 337, 350, 352, 353, 354, 355, 357, 358, 359, 365, …, .
.5: 3, 5, 7, 9, 23, 25, 27, 29, 30, 33, 39, 43, 47, 49, 50, 53, 55, 57, 59, 65, 67, 69, 70, 73, …, .
.6: 28, 94, 228, 268, 272, 274, 280, 282, 294, 328, 394, 428, 494, 528, 594, 694, 728, 828, 894, …, .
.7: 54, 68, 82, 248, 252, 254, 382, 388, 392, 398, 468, 482, 532, 534, 538, 540, 542, 554, 568, …, .
.8: 48, 98, 232, 234, 298, 348, 480, 484, 498, 548, 598, 698, 732, 734, 748, 848, 898, 980, 984, …, .
.9: 22, 88, 220, 222, 288, 322, 324, 332, 422, 488, 522, 552, 588, 658, 688, 722, 880, 884, 888, …, .
10: 2, 4, 8, 20, 24, 32, 34, 38, 40, 42, 52, 58, 72, 74, 80, 84, 92, 200, 202, 204, 208, 224, …, .

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{k = 1}, While[ Intersection[ IntegerDigits[k], IntegerDigits[n*k]] == {}, k++]; k]; Array[f, 100]

Formula

If a(n) = k so does a(10n).

A038365 Numbers n with property that digits of n are not present in 2n.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, 16, 17, 18, 19, 22, 23, 27, 28, 29, 31, 32, 33, 34, 35, 36, 38, 39, 41, 43, 44, 45, 46, 48, 52, 53, 54, 55, 56, 57, 58, 59, 64, 65, 66, 67, 69, 72, 73, 76, 77, 78, 79, 82, 83, 85, 86, 88, 92, 93, 94, 111, 113, 114, 115, 116, 117, 118
Offset: 1

Views

Author

Keywords

Comments

207 is the smallest number containing a zero, cf. A192825. [Reinhard Zumkeller, Aug 09 2011]

Examples

			36 is in the list since 2*36=72, which shares no digit with 36.
		

Crossrefs

Cf. A129845 (complement).

Programs

  • Haskell
    import Data.List (intersect)
    a038365 n = a038365_list !! (n-1)
    a038365_list = filter (\x -> null (show (2*x) `intersect` show x)) [1..]
    -- Reinhard Zumkeller, Aug 09 2011
  • Mathematica
    Select[Range[140],Intersection[IntegerDigits[2 #], IntegerDigits[#]] =={}&]  (* Harvey P. Dale, Apr 30 2011 *)
Showing 1-7 of 7 results.