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.

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A033009 Every run of digits of n in base 11 has length 2.

Original entry on oeis.org

12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 1452, 1476, 1488, 1500, 1512, 1524, 1536, 1548, 1560, 1572, 2904, 2916, 2940, 2952, 2964, 2976, 2988, 3000, 3012, 3024, 4356, 4368, 4380, 4404, 4416, 4428, 4440, 4452, 4464, 4476
Offset: 1

Views

Author

Keywords

Comments

See A043291 and A033001 through A033014 for the analog in other bases, A033015 - A033029 for the variants with run lengths >= 2. - M. F. Hasler, Feb 02 2014

Programs

  • Mathematica
    Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 11]]]=={2}&] (* Vincenzo Librandi, Feb 05 2014 *)

Formula

a(n) = 12*A043315(n) (= 12*n for n<11). - M. F. Hasler, Feb 02 2014

A033011 Every run of digits of n in base 13 has length 2.

Original entry on oeis.org

14, 28, 42, 56, 70, 84, 98, 112, 126, 140, 154, 168, 2366, 2394, 2408, 2422, 2436, 2450, 2464, 2478, 2492, 2506, 2520, 2534, 4732, 4746, 4774, 4788, 4802, 4816, 4830, 4844, 4858, 4872, 4886, 4900, 7098, 7112, 7126, 7154
Offset: 1

Views

Author

Keywords

Comments

See A043291 and A033001 through A033014 for the analog in other bases. See A033015 through A033029 for the variants with run lengths >= 2. - M. F. Hasler, Feb 02 2014

Programs

  • Mathematica
    Select[Range[8000],Union[Length/@Split[IntegerDigits[#,13]]]=={2}&] (* Harvey P. Dale, Feb 27 2013 *)

Formula

a(n) = 14*A043317(n) (= 14*n for n<13). - M. F. Hasler, Feb 02 2014

A033012 Every run of digits of n in base 14 has length 2.

Original entry on oeis.org

15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 2940, 2970, 2985, 3000, 3015, 3030, 3045, 3060, 3075, 3090, 3105, 3120, 3135, 5880, 5895, 5925, 5940, 5955, 5970, 5985, 6000, 6015, 6030, 6045, 6060, 6075, 8820
Offset: 1

Views

Author

Keywords

Comments

See A043291 and A033001 through A033014 for the analog in other bases, A033015 - A033029 for the variants with run lengths >= 2. - M. F. Hasler, Feb 04 2014

Programs

  • Mathematica
    Select[Range[9000],Union[Length/@Split[IntegerDigits[#,14]]]=={2}&] (* Harvey P. Dale, Apr 26 2013 *)

Formula

a(n) = 15*A043318(n) (= 15*n for n<14). - M. F. Hasler, Feb 02 2014

A033013 Every run of digits of n in base 15 has length 2.

Original entry on oeis.org

16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 3600, 3632, 3648, 3664, 3680, 3696, 3712, 3728, 3744, 3760, 3776, 3792, 3808, 3824, 7200, 7216, 7248, 7264, 7280, 7296, 7312, 7328, 7344, 7360, 7376, 7392
Offset: 1

Views

Author

Keywords

Comments

See A043291 and A033001 through A033014 for the analog in other bases, A033015 - A033029 for the variants with run lengths >= 2. - M. F. Hasler, Feb 04 2014

Programs

  • Mathematica
    Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 15]]]=={2}&] (* Vincenzo Librandi, Feb 05 2014 *)

Formula

a(n) = 16*A043319(n) (= 16n for n<15). - M. F. Hasler, Feb 02 2014

A043308 a(n)=A033002(n)/5.

Original entry on oeis.org

1, 2, 3, 16, 18, 19, 32, 33, 35, 48, 49, 50, 257, 258, 259, 288, 289, 291, 304, 305, 306, 513, 514, 515, 528, 530, 531, 560, 561, 562, 769, 770, 771, 784, 786, 787, 800, 801, 803, 4112, 4114, 4115, 4128, 4129, 4131, 4144, 4145
Offset: 1

Views

Author

Keywords

Comments

Also: Numbers which, written in base 16, have all digits less than 4 and no two adjacent digits equal. - M. F. Hasler, Feb 03 2014

Crossrefs

Programs

  • PARI
    is_A043308(n)=(n=[n])&&!until(!n[1],((n=divrem(n[1],16))[2]<4 && n[1]%4!=n[2])||return) \\ M. F. Hasler, Feb 03 2014

A043312 a(n) = A033006(n)/9.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 64, 66, 67, 68, 69, 70, 71, 128, 129, 131, 132, 133, 134, 135, 192, 193, 194, 196, 197, 198, 199, 256, 257, 258, 259, 261, 262, 263, 320, 321, 322, 323, 324, 326, 327, 384, 385, 386, 387, 388, 389, 391, 448, 449
Offset: 1

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Author

Keywords

Comments

Also: Numbers which, written in base 64, have only digits 0 through 7, and no two adjacent digits equal. - M. F. Hasler, Feb 03 2014

Crossrefs

Programs

  • Maple
    f:= proc(n) local i;
          seq(64*n+i, i= subs(n mod 64 = NULL, [$0..7]))
    end proc:
    A:= $1..7: R:= [A]:
    for d from 2 to 3 do
      R:= map(f, R);
      A:= A, op(R);
    od:
    A; # Robert Israel, Jun 11 2019
  • PARI
    is_A043312(n)=(n=[n])&&!until(!n[1],((n=divrem(n[1],64))[2]<8 && n[1]%8!=n[2])||return) \\ M. F. Hasler, Feb 03 2014

A043317 a(n)=A033011(n)/14.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 169, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 338, 339, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 507, 508, 509, 511, 512, 513, 514, 515, 516, 517, 518, 519, 676, 677, 678
Offset: 1

Views

Author

Keywords

Comments

Also: Numbers which, written in base 169, have all digits less than 13 and no two adjacent digits equal. - M. F. Hasler, Feb 03 2014

Crossrefs

Programs

  • Mathematica
    Select[Range[700],Max[IntegerDigits[#,169]]<13&&SequenceCount[ IntegerDigits[ #,169],{x_,x_}]==0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 07 2018 *)
  • PARI
    is_A043317(n)=(n=[n])&&!until(!n[1],((n=divrem(n,169))[2]<13 && n[2]!=n[1]%13)||return) \\ M. F. Hasler, Feb 03 2014

A043319 a(n)=A033013(n)/16.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 225, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 450, 451, 453, 454, 455, 456, 457, 458, 459, 460, 461, 462, 463, 464, 675, 676, 677, 679, 680, 681, 682, 683, 684
Offset: 1

Views

Author

Keywords

Comments

Also: Numbers which, written in base 225, have all digits less than 15 and no two adjacent digits equal. - M. F. Hasler, Feb 03 2014

Crossrefs

Programs

  • PARI
    is_A043319(n)=(n=[n])&&!until(!n[1], ((n=divrem(n[1], 225))[2]<15 && n[1]%15!=n[2])||return) \\ M. F. Hasler, Feb 03 2014

A154806 Numbers such that every run length in base 2 is 4.

Original entry on oeis.org

15, 240, 3855, 61680, 986895, 15790320, 252645135, 4042322160, 64677154575, 1034834473200, 16557351571215, 264917625139440, 4238682002231055, 67818912035696880, 1085102592571150095, 17361641481138401520
Offset: 1

Views

Author

Omar E. Pol, Jan 25 2009

Keywords

Comments

a(n) is the number whose binary representation is A154805(n).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{16,1,-16},{15,240,3855},20] (* Harvey P. Dale, Apr 13 2018 *)

Formula

Conjecture: a(n) = 1/17*2^(4*n+4) + 15/34*(-1)^(n+1) - 1/2. - Vaclav Kotesovec, Nov 30 2012
Empirical g.f.: 15*x / ((x-1)*(x+1)*(16*x-1)). - Colin Barker, Sep 16 2013

Extensions

More terms from Sean A. Irvine, Feb 21 2010

A249907 Smallest positive integer k such that k contains all possible pairs of digits when represented in base b = n >= 2.

Original entry on oeis.org

19, 20842, 4387884733, 301083852338952371, 10372871309299412994565980691, 257810894191937039020949293796466032151538, 6291283822228991408060146690794416231996294644948906012153, 196933489270977741064964174271054692081510750312035993579769632880958095885917
Offset: 2

Views

Author

Anthony Sand, Nov 08 2014

Keywords

Comments

In base b, there are b^2 distinct pairs of digits and the smallest positive integer to contain all of them will have (b^2)+1 digits. For example, in base 2 there are 2^2 = 4 distinct pairs: 00, 01, 10, 11. All of them are represented in the 5-digit binary number 10011 = 19 in base 10.

Examples

			n = 2: a(2) = 19 = 10011 in base 2, which contains 4 distinct pairs of digits: 10, 00, 01, 11.
n = 3: a(3) = 20842 = 1001120221 in base 3, which contains 9 distinct pairs of digits: 10, 00, 01, 11, 12, 20, 22, 21.
n = 4: a(4) = 4387884733 = 10011202130322331 in base 4, which contains 16 distinct pairs of digits: 10, 00, 01, 11, 12, 20, 02, 21, 13, 30, 03, 32, 22, 23, 33, 31.
In base 10, all pairs from 00 to 99 are found in the 101 digits of [1, 0, 0, 1, 1, 2, 0, 2, 1, 3, 0, 3, 1, 4, 0, 4, 1, 5, 0, 5, 1, 6, 0, 6, 1, 7, 0, 7, 1, 8, 0, 8, 1, 9, 0, 9, 2, 2, 3, 2, 4, 2, 5, 2, 6, 2, 7, 2, 8, 2, 9, 3, 3, 4, 3, 5, 3, 6, 3, 7, 3, 8, 3, 9, 4, 4, 5, 4, 6, 4, 7, 4, 8, 4, 9, 5, 5, 6, 5, 7,5, 8, 5, 9, 6, 6, 7, 6, 8, 6, 9, 7, 7, 8, 7, 9, 8, 8, 9, 9, 1].
		

Crossrefs

Extensions

Edited: minor changes in the name, comment and example. - Wolfdieter Lang, Nov 21 2014
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