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 21 results. Next

A138255 Smallest positive integer m such that n divides [2^m/m] (=A000799(m)).

Original entry on oeis.org

1, 1, 5, 4, 6, 5, 9, 8, 7, 6, 12, 15, 14, 9, 13, 8, 10, 7, 21, 28, 13, 24, 48, 15, 22, 14, 19, 9, 30, 13, 11, 8, 31, 10, 13, 21, 38, 21, 14, 39, 22, 13, 29, 63, 13, 67, 135, 65, 43, 22, 10, 15, 35, 19, 24, 9, 21, 30, 120, 28, 62, 11, 13, 16, 14, 31, 69, 20, 67, 13, 145, 21, 19, 38
Offset: 1

Views

Author

Max Alekseyev, Mar 09 2008

Keywords

Comments

This sequence is well-defined.

Crossrefs

Programs

  • Maple
    f:= proc(n) local m;
         for m from 1 do if floor(2^m/m) mod n = 0 then return m fi od
    end proc:
    map(f, [$1..100]); # Robert Israel, Jun 07 2018
  • Mathematica
    a[n_] := For[m = 1, True, m++, If[Divisible[Floor[2^m/m], n], Return[m]]];
    Array[a, 100] (* Jean-François Alcover, Mar 22 2019 *)
  • Python
    from itertools import count
    def A138255(n): return next(m for m in count(1) if not (1<Chai Wah Wu, Aug 24 2023

A114699 A000799(n) - A064355(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 3, 0, 0, 6, 0, 0, 10, 1, 0, 18, 0, 0, 36, 0, 0, 62, 0, 4, 113, 0, 0, 210, 6, 0, 391, 0, 0, 739, 0, 0, 1365, 2, 20, 2570, 0, 0, 4854, 37, 4, 9198, 0, 0, 17544, 0, 0, 33296, 0, 126, 63550, 0, 0, 121574, 248, 0, 233016, 0, 0, 447828, 0
Offset: 0

Views

Author

Paul D. Hanna, Feb 20 2006

Keywords

Comments

There was a suggestion that these were the same sequence, but they are not.

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{d = Select[Divisors@n, OddQ@# &]}, Floor[2^n/n] - Plus @@ (2^(n/d)*MoebiusMu@d)/n]; Array[f, 76] (* Robert G. Wilson v *)

Formula

A000799(n) = A064355(n) just for: (1) n a power of 2. (2) n = p * 2^k, where p is a prime with p > 2^{2^k - k}. (Including the case k=0. ) (3) n = 9. -Franklin T. Adams-Watters, Feb 14 2006

Extensions

More terms from Robert G. Wilson v, Feb 20 2006

A092763 a(n) = floor(3^n / n).

Original entry on oeis.org

3, 4, 9, 20, 48, 121, 312, 820, 2187, 5904, 16104, 44286, 122640, 341640, 956593, 2690420, 7596480, 21523360, 61171656, 174339220, 498112057, 1426411800, 4093181688, 11767897353, 33891544377, 97764070320, 282429536481
Offset: 1

Views

Author

Reinhard Zumkeller, Apr 13 2004

Keywords

Comments

a(n) = (A000244(n) - A066601(n))/n.

Crossrefs

Cf. A000799.

Programs

A129795 a(n) = floor(5^n/n).

Original entry on oeis.org

5, 12, 41, 156, 625, 2604, 11160, 48828, 217013, 976562, 4438920, 20345052, 93900240, 435965401, 2034505208, 9536743164, 44878791360, 211927625868, 1003867701480, 4768371582031, 22706531343005, 108372081409801
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A003176 Integer part of 24(2^n-1)/n.

Original entry on oeis.org

24, 36, 56, 90, 148, 252, 435, 765, 1362, 2455, 4466, 8190, 15121, 28085, 52427, 98302, 185041, 349524, 662257, 1258290, 2396744, 4575603, 8753329, 16777215, 32212253, 61946642, 119304646, 230087532
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [Floor(24*(2^n-1)/n): n in [1..45]]; // Vincenzo Librandi, May 08 2011
    
  • Mathematica
    a[n_] := Floor[24*(2^n-1)/n]; Array[a, 30] (* Giovanni Resta, Mar 25 2017 *)
  • Python
    def A003176(n): return ((3<Chai Wah Wu, Aug 24 2023

A060155 Table T(n,k) by antidiagonals of floor(n^k/k) [n,k >= 1].

Original entry on oeis.org

1, 0, 2, 0, 2, 3, 0, 2, 4, 4, 0, 4, 9, 8, 5, 0, 6, 20, 21, 12, 6, 0, 10, 48, 64, 41, 18, 7, 0, 18, 121, 204, 156, 72, 24, 8, 0, 32, 312, 682, 625, 324, 114, 32, 9, 0, 56, 820, 2340, 2604, 1555, 600, 170, 40, 10, 0, 102, 2187, 8192, 11160, 7776, 3361, 1024, 243, 50, 11
Offset: 1

Views

Author

Henry Bottomley, Mar 12 2001

Keywords

Examples

			T(5,3)=[5^3/3]=[125/3]=41.
Rows start:
  1,  0,  0,   0,   0, ...
  2,  2,  2,   4,   6, ...
  3,  4,  9,  20,  48, ...
  4,  8, 21,  64, 204, ...
  5, 12, 41, 156, 625, ...
		

Crossrefs

Columns include A000027, A007590.
Diagonals include A000169.

Formula

T(n, k) = (A051129(n, k)-A060154(n, k))/k.

A060156 a(n) = floor(10^n/n).

Original entry on oeis.org

10, 50, 333, 2500, 20000, 166666, 1428571, 12500000, 111111111, 1000000000, 9090909090, 83333333333, 769230769230, 7142857142857, 66666666666666, 625000000000000
Offset: 1

Views

Author

Henry Bottomley, Mar 12 2001

Keywords

Examples

			a(6) = floor(1000000/6) = 166666.
		

Crossrefs

Programs

  • PARI
    { default(realprecision, 10); for (n=1, 200, write("b060156.txt", n, " ", floor(10^n/n)); ) } \\ Harry J. Smith, Jul 02 2009

Formula

a(n) = (A011557(n) - A056969(n))/n.

A082493 a(n) = n*ceiling(2^n/n) - 2^n.

Original entry on oeis.org

0, 0, 1, 0, 3, 2, 5, 0, 1, 6, 9, 8, 11, 10, 7, 0, 15, 8, 17, 4, 13, 18, 21, 8, 18, 22, 1, 12, 27, 26, 29, 0, 25, 30, 17, 8, 35, 34, 31, 24, 39, 20, 41, 28, 28, 42, 45, 32, 19, 26, 43, 36, 51, 26, 12, 24, 49, 54, 57, 44, 59, 58, 55, 0, 33, 2, 65, 52, 61, 26, 69, 8, 71, 70, 7, 60, 59, 14
Offset: 1

Views

Author

Vladeta Jovovic, Apr 28 2003

Keywords

Comments

Least nonnegative k such that (2^n+k)/n is an integer.
If n is a power of 2, a(n) = 0; otherwise a(n) = n - A015910(n). - Robert Israel, Apr 08 2015

Crossrefs

Programs

Formula

a(n) = -(2^n) mod n. - Robert Israel, Apr 08 2015

A129794 a(n) = floor(4^n/n).

Original entry on oeis.org

4, 8, 21, 64, 204, 682, 2340, 8192, 29127, 104857, 381300, 1398101, 5162220, 19173961, 71582788, 268435456, 1010580540, 3817748707, 14467258260, 54975581388, 209430786243, 799644820200, 3059510616420, 11728124029610
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A129796 a(n) = floor(6^n/n).

Original entry on oeis.org

6, 18, 72, 324, 1555, 7776, 39990, 209952, 1119744, 6046617, 32981550, 181398528, 1004668770, 5597440292, 31345665638, 176319369216, 995685849690, 5642219814912, 32071565263710, 182807922003148, 1044616697160850
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

Showing 1-10 of 21 results. Next