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 1-9 of 9 results.

A227842 First differences of A014817.

Original entry on oeis.org

1, 2, 3, 2, 4, 5, 6, 5, 5, 8, 9, 6, 10, 11, 12, 7, 13, 12, 15, 12, 14, 17, 18, 13, 15, 20, 19, 16, 22, 21, 24, 17, 21, 26, 27, 18, 26, 29, 28, 21, 29, 28, 33, 28, 30, 33, 36, 27, 31, 34, 35, 32, 38, 39, 40, 31, 37, 42, 45, 32, 44, 45, 46, 33, 45, 44, 49, 44, 46, 51, 52, 37, 49, 56, 49, 48, 54, 53, 60, 47
Offset: 1

Views

Author

N. J. A. Sloane, Aug 08 2013

Keywords

Crossrefs

Programs

A227841 Partial sums of A014817.

Original entry on oeis.org

1, 3, 7, 14, 23, 36, 54, 78, 107, 141, 183, 234, 291, 358, 436, 526, 623, 733, 855, 992, 1141, 1304, 1484, 1682, 1893, 2119, 2365, 2630, 2911, 3214, 3538, 3886, 4251, 4637, 5049, 5488, 5945, 6428, 6940, 7480, 8041, 8631, 9249, 9900, 10579, 11288, 12030
Offset: 1

Views

Author

N. J. A. Sloane, Aug 08 2013

Keywords

Crossrefs

Programs

  • Mathematica
    Accumulate[Table[Sum[Floor[k^2/n],{k,n}],{n,50}]] (* Harvey P. Dale, Sep 27 2023 *)

A166375 a(n) = sum (floor (j^2/n)) taken over 1 <= j <= n-1.

Original entry on oeis.org

0, 1, 3, 4, 7, 11, 16, 20, 24, 31, 39, 44, 53, 63, 74, 80, 92, 103, 117, 128, 141, 157, 174, 186, 200, 219, 237, 252, 273, 293, 316, 332, 352, 377, 403, 420, 445, 473, 500, 520, 548, 575, 607, 634, 663, 695, 730, 756, 786, 819, 853, 884, 921, 959, 998
Offset: 2

Views

Author

Keywords

Crossrefs

Row sums of A166373. Cf. A014817.

Programs

  • Maple
    A166375 := proc(n)
        add( floor(j^2/n),j=1..n-1) ;
    end proc: # R. J. Mathar, Jul 21 2015
  • Mathematica
    Table[Sum[Floor[k^2/n], {k, 1, n - 1}], {n, 2, 100}] (* G. C. Greubel, May 10 2016 *)
  • PARI
    a(n) = sum(j=1,n-1, j^2\n) \\ Michel Marcus, Jun 20 2013

Formula

a(n) = A014817(n) - n. - R. J. Mathar, Jul 21 2015

A165993 a(n) = sum_{j=1..prime(n)-1} floor (j^2/prime(n)).

Original entry on oeis.org

0, 1, 4, 11, 31, 44, 80, 103, 157, 252, 293, 420, 520, 575, 695, 884, 1105, 1180, 1431, 1617, 1704, 2007, 2217, 2552, 3040, 3300, 3439, 3713, 3852, 4144, 5255, 5595, 6120, 6305, 7252, 7457, 8060, 8695, 9141, 9804, 10507, 10740, 11983, 12224, 12740
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Floor[j^2/n],{j,n-1}],{n,Prime[Range[50]]}] (* Harvey P. Dale, Aug 10 2014 *)
  • PARI
    a(n) = sum(j=1, prime(n)-1, floor (j^2/prime(n))) \\ Michel Marcus, Jun 20 2013
    
  • PARI
    a(n)=my(p=prime(n));sum(j=1,p-1,j^2\p) \\ Charles R Greathouse IV, Jun 20 2013

Formula

a(n) = A166375(prime(n)-1). - Charles R Greathouse IV, Jun 28 2013

Extensions

Definition rephrased by R. J. Mathar, Oct 09 2009

A177041 Sum(round(k^2/n),k=1..n).

Original entry on oeis.org

1, 3, 4, 7, 11, 16, 20, 26, 31, 39, 44, 53, 63, 74, 82, 94, 105, 119, 128, 141, 157, 174, 188, 204, 221, 239, 254, 275, 295, 318, 336, 360, 377, 403, 422, 447, 475, 502, 526, 554, 581, 611, 636, 665, 697, 732, 760, 794, 825, 861
Offset: 1

Views

Author

Mircea Merca, Dec 09 2010

Keywords

Comments

The round function, also called the nearest integer function, is defined here by round(x)=floor(x+1/2).

Crossrefs

Cf. A014817.

Programs

  • Maple
    A177041 := proc(n)
        add( round(j^2/n),j=1..n) ;
    end proc:
  • Mathematica
    Table[Sum[Floor[k^2/n + 1/2], {k, n}], {n, 50}]

A014818 a(n) is the sum over all floor(k^3/n), k=0 to n inclusive.

Original entry on oeis.org

1, 4, 11, 24, 43, 71, 109, 160, 222, 298, 391, 502, 631, 781, 953, 1150, 1369, 1617, 1891, 2196, 2531, 2899, 3301, 3740, 4215, 4726, 5283, 5874, 6511, 7193, 7921, 8700, 9521, 10396, 11323, 12306, 13339, 14431, 15581, 16792, 18061, 19394, 20791, 22254, 23784
Offset: 1

Views

Author

Keywords

References

  • M. Eichler and D. Zagier, The Theory of Jacobi Forms, Birkhauser, 1985, p. 103.

Crossrefs

Programs

  • Magma
    [&+[Floor(k^3/n): k in [1..n]]: n in [1..50]]; // Vincenzo Librandi, Feb 12 2017
    
  • Maple
    f := m->sum( floor(k^3 / m), k=0..m);
  • Mathematica
    Table[Sum[Floor[k^3 / n], {k, n}], {n, 50}] (* Vincenzo Librandi, Feb 12 2017 *)
  • PARI
    a(n) = sum(k=0, n, k^3\n); \\ Michel Marcus, Feb 12 2017

A014819 a(n) = Sum_{k=1..n} floor(k^4/n).

Original entry on oeis.org

1, 8, 32, 88, 195, 377, 666, 1096, 1701, 2530, 3630, 5056, 6863, 9115, 11884, 15240, 19249, 24012, 29606, 36126, 43665, 52327, 62220, 73452, 86137, 100398, 116364, 134158, 153915, 175789, 199908, 226432, 255501, 287288, 321958, 359672, 400599, 444927, 492842
Offset: 1

Views

Author

Keywords

References

  • M. Eichler and D. Zagier, The Theory of Jacobi Forms, Birkhauser, 1985, p. 103.

Crossrefs

Programs

  • Magma
    [(&+[Floor(k^4/n): k in [1..n]]): n in [1..40]]; // G. C. Greubel, Nov 21 2018
    
  • Maple
    f := m-> add( floor((nu)^4/m), nu=0..m): seq(f(n), n=1..40);
  • Mathematica
    Table[Sum[Floor[k^4/n], {k, 1, n}], {n, 1, 40}] (* G. C. Greubel, Nov 21 2018 *)
  • PARI
    vector(40, n, sum(k=1,n, floor(k^4/n))) \\ G. C. Greubel, Nov 21 2018
    
  • Sage
    [sum(floor(k^4/n) for k in (1..n)) for n in (1..40)] # G. C. Greubel, Nov 21 2018

Extensions

Title improved by Sean A. Irvine, Nov 21 2018

A175908 3*sum(k=1..n, floor(k^2/n)) - n^2.

Original entry on oeis.org

2, 2, 3, 5, 2, 3, 5, 8, 6, 2, 5, 9, 2, 5, 9, 14, 2, 6, 5, 11, 6, 5, 11, 18, 8, 2, 9, 11, 2, 9, 11, 20, 6, 2, 11, 21, 2, 5, 15, 20, 2, 6, 5, 17, 12, 11, 17, 30, 14, 8, 9, 11, 2, 9, 17, 26, 6, 2, 11, 27, 2, 11, 21, 32, 2, 6, 5, 17, 12, 11, 23, 36, 2, 2, 21, 17, 8, 15, 17, 38
Offset: 1

Views

Author

John W. Layman, Oct 14 2010

Keywords

Comments

According to the reference, a(p*q) = a(p) + a(q) - 2 whenever p and q are distinct primes with p congruent to q modulo 4.
The sequences of indices n where a(n)=2 is {1, 2, 5, 10, 13, 17, 26, ...}, which appears to be A020893 (squarefree sums of two squares). This has been confirmed for the first 500 terms. [John W. Layman, May 16 2011]

Crossrefs

Cf. A020893.

Programs

Formula

a(n) = 3*A014817(n) - A000290(n). - Wesley Ivan Hurt, Jul 10 2014

A014785 a(n) = Sum_{0<=k<=n} ceiling(k^2/n).

Original entry on oeis.org

1, 3, 6, 9, 13, 18, 24, 30, 35, 43, 52, 61, 69, 80, 92, 102, 113, 125, 140, 155, 169, 184, 202, 220, 231, 251, 270, 291, 309, 332, 354, 376, 397, 419, 446, 469, 493, 520, 550, 578, 601, 631, 660, 693, 721, 754, 788
Offset: 1

Views

Author

Keywords

References

  • M. Eichler and D. Zagier, The Theory of Jacobi Forms, Birkhauser, 1985, p. 103.

Crossrefs

Cf. A014817 (with floor), A177041 (with round).

Programs

  • Magma
    [&+[Ceiling(k^2/n):k in [0..n]]:n in [1..50]]; // Marius A. Burtea, Dec 31 2019
  • Maple
    f := n->sum( ceil(k^2/n), k=0..n);
  • Mathematica
    Table[Sum[Ceiling[k^2/n],{k,0,n}],{n,50}] (* Harvey P. Dale, Oct 24 2013 *)
Showing 1-9 of 9 results.