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 13 results. Next

A212455 a(n) = floor(2n*log(2n)).

Original entry on oeis.org

1, 5, 10, 16, 23, 29, 36, 44, 52, 59, 68, 76, 84, 93, 102, 110, 119, 129, 138, 147, 156, 166, 176, 185, 195, 205, 215, 225, 235, 245, 255, 266, 276, 286, 297, 307, 318, 329, 339, 350, 361, 372, 383, 394, 404, 416, 427
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(FLOOR(2·x·LOG(2·x)), y), x := x - 1))
    
  • Magma
    [Floor(2*n*Log(2*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Floor[2*n*Log[2*n]], {n, 60}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n)=2*n*log(2*n)\1 \\ Charles R Greathouse IV, Sep 04 2015

A212456 a(n) = floor(3n*log(3n)).

Original entry on oeis.org

3, 10, 19, 29, 40, 52, 63, 76, 88, 102, 115, 129, 142, 156, 171, 185, 200, 215, 230, 245, 261, 276, 292, 307, 323, 339, 355, 372, 388, 404, 421, 438, 454, 471, 488, 505, 522, 539, 557, 574, 591, 609, 626, 644, 662, 679
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(FLOOR(3·x·LOG(3·x)), y), x := x - 1))
    
  • Magma
    [Floor(3*n*Log(3*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Floor[3*n*Log[3*n]], {n, 60}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n)=3*n*log(3*n)\1 \\ Charles R Greathouse IV, Sep 04 2015

A212457 a(n) = floor(4n*log(4n)).

Original entry on oeis.org

5, 16, 29, 44, 59, 76, 93, 110, 129, 147, 166, 185, 205, 225, 245, 266, 286, 307, 329, 350, 372, 394, 416, 438, 460, 483, 505, 528, 551, 574, 597, 621, 644, 668, 691, 715, 739, 763, 787, 812, 836, 860, 885, 910, 934
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(FLOOR(4·x·LOG(4·x)), y), x := x - 1))
    
  • Magma
    [Floor(4*n*Log(4*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Floor[4*n*Log[4*n]], {n, 80}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n)=4*n*log(4*n)\1 \\ Charles R Greathouse IV, Sep 04 2015

A212458 a(n) = floor(5n*log(5n)).

Original entry on oeis.org

8, 23, 40, 59, 80, 102, 124, 147, 171, 195, 220, 245, 271, 297, 323, 350, 377, 404, 432, 460, 488, 517, 545, 574, 603, 632, 662, 691, 721, 751, 781, 812, 842, 873, 903, 934, 965, 996, 1028, 1059, 1091, 1122, 1154, 1186
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(FLOOR(5·x·LOG(5·x)), y), x := x - 1))
    
  • Magma
    [Floor(5*n*Log(5*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Floor[5*n*Log[5*n]], {n, 80}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n)=5*n*log(5*n)\1 \\ Charles R Greathouse IV, Sep 04 2015

A212459 a(n) = ceiling(2n*log(2n)).

Original entry on oeis.org

2, 6, 11, 17, 24, 30, 37, 45, 53, 60, 69, 77, 85, 94, 103, 111, 120, 130, 139, 148, 157, 167, 177, 186, 196, 206, 216, 226, 236, 246, 256, 267, 277, 287, 298, 308, 319, 330, 340, 351, 362, 373, 384, 395, 405, 417, 428
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(CEILING(2·x·LOG(2·x)), y), x := x - 1))
    
  • Magma
    [Ceiling(2*n*Log(2*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Ceiling[2*n*Log[2*n]], {n, 80}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n) = ceil(2*n*log(2*n)); \\ Michel Marcus, Jan 11 2016

Formula

a(n) = A050502(2*n). - Michel Marcus, Jan 11 2016

A212460 a(n) = ceiling(3n*log(3n)).

Original entry on oeis.org

4, 11, 20, 30, 41, 53, 64, 77, 89, 103, 116, 130, 143, 157, 172, 186, 201, 216, 231, 246, 262, 277, 293, 308, 324, 340, 356, 373, 389, 405, 422, 439, 455, 472, 489, 506, 523, 540, 558, 575, 592, 610, 627, 645, 663, 680
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(CEILING(3·x·LOG(3·x)), y), x := x - 1))
    
  • Magma
    [Ceiling(3*n*Log(3*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Ceiling[3*n*Log[3*n]], {n, 80}] (* Vincenzo Liobrandi, Feb 13 2013 *)
  • PARI
    a(n) = ceil(3*n*log(3*n)); \\ Michel Marcus, Jan 11 2016

Formula

a(n) = A050502(3*n). - Michel Marcus, Jan 11 2016

A212461 a(n) = ceiling(4n*log(4n)).

Original entry on oeis.org

6, 17, 30, 45, 60, 77, 94, 111, 130, 148, 167, 186, 206, 226, 246, 267, 287, 308, 330, 351, 373, 395, 417, 439, 461, 484, 506, 529, 552, 575, 598, 622, 645, 669, 692, 716, 740, 764, 788, 813, 837, 861, 886, 911, 935
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(CEILING(4·x·LOG(4·x)), y), x := x - 1))
    
  • Magma
    [Ceiling(4*n*Log(4*n)): n in [1..80]]; // Vincenzo Librandi, Feb 13 2013
    
  • Mathematica
    Table[Ceiling[4*n*Log[4*n]], {n, 80}] (* Vincenzo Librandi, Feb 13 2013 *)
  • PARI
    a(n) = ceil(4*n*log(4*n)); \\ Michel Marcus, Jan 11 2016

Formula

a(n) = A050502(4*n). - Michel Marcus, Jan 11 2016

A212462 a(n) = ceiling(5n*log(5n)).

Original entry on oeis.org

9, 24, 41, 60, 81, 103, 125, 148, 172, 196, 221, 246, 272, 298, 324, 351, 378, 405, 433, 461, 489, 518, 546, 575, 604, 633, 663, 692, 722, 752, 782, 813, 843, 874, 904, 935, 966, 997, 1029, 1060, 1092, 1123, 1155
Offset: 1

Views

Author

Mohammad K. Azarian, May 31 2012

Keywords

Crossrefs

Programs

  • Derive
    PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(CEILING(5·x·LOG(5·x)), y), x := x - 1))
    
  • Magma
    [Ceiling(5*n*Log(5*n)): n in [1..80]]; // Vincenzo Librandi, Feb 14 2013
    
  • Mathematica
    Table[Ceiling[5*n*Log[5*n]], {n, 80}] (* Vincenzo Librandi, Feb 14 2013 *)
  • PARI
    a(n) = ceil(5*n*log(5*n)); \\ Michel Marcus, Jan 11 2016

Formula

a(n) = A050502(5*n). - Michel Marcus, Jan 11 2016

A050503 Nearest integer to n*log(n).

Original entry on oeis.org

0, 1, 3, 6, 8, 11, 14, 17, 20, 23, 26, 30, 33, 37, 41, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 85, 89, 93, 98, 102, 106, 111, 115, 120, 124, 129, 134, 138, 143, 148, 152, 157, 162, 167, 171, 176, 181, 186, 191, 196, 201, 205, 210, 215, 220, 225, 230, 236, 241
Offset: 1

Views

Author

N. J. A. Sloane, Dec 27 1999

Keywords

Comments

The prime number theorem states that the n-th prime is asymptotic to n*log(n).

References

  • G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, Theorem 8.

Crossrefs

Programs

  • Mathematica
    Table[Round[n Log[n]],{n,100}] (* Harvey P. Dale, Sep 27 2023 *)

A135736 Nearest integer to n*Sum_{k=1..n} 1/k = rounded expected coupon collection numbers.

Original entry on oeis.org

0, 1, 3, 6, 8, 11, 15, 18, 22, 25, 29, 33, 37, 41, 46, 50, 54, 58, 63, 67, 72, 77, 81, 86, 91, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 161, 166, 171, 176, 182, 187, 192, 198, 203, 209, 214, 219, 225, 230, 236, 242, 247, 253, 258, 264, 269, 275
Offset: 0

Views

Author

M. F. Hasler, Nov 29 2007

Keywords

Comments

Somewhat more realistic than A052488 but more optimistic than A060293, the expected number of boxes that must be bought to get the full collection of N objects, if each box contains any one of them at random. See also comments in A060293, A052488.

Examples

			a(0) = 0 since nothing needs to be bought if nothing is to be collected.
a(1) = 1 since only 1 box needs to be bought if only 1 object is to be collected.
a(2) = 3 since the chance of getting the other object at the second purchase is only 1/2, so it takes 2 boxes on the average to get it.
a(3) = 6 since the chance of getting a new object at the second purchase is 2/3 so it takes 3/2 boxes in the mean, then the chance becomes 1/3 to get the 3rd, i.e., 3 other boxes on the average to get the full collection and the rounded value of 1 + 3/2 + 3 = 11/2 = 5.5 is 6.
		

Crossrefs

Programs

  • Maple
    seq(round(n*harmonic(n)), n=1..100); # Robert Israel, Oct 31 2016
  • Mathematica
    Table[Round[n*Sum[1/k, {k, 1, n}]], {n,0,25}] (* G. C. Greubel, Oct 29 2016 *)
  • PARI
    A135736(n)=round(n*sum(i=1,n,1/i))
    
  • Python
    n=100 #set the number of terms you want to calculate here
    ans=0
    finalans = []
    finalans.append(0) #continuity with A135736
    for i in range(1, n+1):
        ans+=(1/i)
        finalans.append(int(round(ans*i)))
    print(finalans)
    # Adam Hugill, Feb 14 2022

Formula

a(n) = round(n*A001008(n)/A002805(n)) = either A052488(n) or A060293(n).
a(n) ~ A060293(n) ~ A052488(n) ~ A050502(n) ~ A050503(n) ~ A050504(n) (asymptotically)
Conjecture: a(n) = round(n*(log(n) + gamma) + 1/2) for n > 0, where gamma = A001620. - Ilya Gutkovskiy, Oct 31 2016
The conjecture is false: a(2416101) = 36905656 while round(2416101*(log(2416101) + gamma) + 1/2) = 36905657, with the unrounded numbers being 36905656.499999982... and 36905656.500000016.... Heuristically this should happen infinitely often. - Charles R Greathouse IV, Oct 31 2016
Showing 1-10 of 13 results. Next