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.

User: Roudy El Haddad

Roudy El Haddad's wiki page.

Roudy El Haddad has authored 13 sequences. Here are the ten most recent ones:

A352980 a(n) = Sum_{1 <= i < j < k <= n} (k*j*i)^3.

Original entry on oeis.org

0, 0, 0, 216, 16280, 335655, 3587535, 25421200, 135459216, 584760870, 2145870870, 6918983280, 20073184560, 53334782501, 131555523645, 304453955520, 666698215360, 1390977293580, 2780695001196, 5351537889480, 9954554649480, 17957698726275
Offset: 0

Author

Roudy El Haddad, Apr 13 2022

Keywords

Comments

a(n) is the sum of all products of three distinct cubes of positive integers up to n, i.e., the sum of all products of three distinct elements from the set of cubes {1^3, ..., n^3}.

Crossrefs

Cf. A352979 (for nondistinct cubes).
Cf. A001303 (for power 1), A000597 (for squares).
Cf. A000578 (cubes), A000537 (sum of first n cubes), A347107 (order 2).

Programs

  • PARI
    {a(n) = n^2 * (n + 1)^2 * (n - 1) * (n - 2) * (35*n^6 + 5*n^5 - 237*n^4 - 77*n^3 + 502*n^2 + 148*n -336)/13440};
    
  • Python
    def A352980(n): return n**2*(n*(n*(n*(n*(n*(n*(n*(n*(n*(35*n - 30) - 347) + 180) + 1365) - 350) - 2541) + 240) + 2160) - 40) - 672)//13440 # Chai Wah Wu, May 15 2022

Formula

a(n) = Sum_{k=3..n} Sum_{j=2..k-1} Sum_{i=1..j-1} k^3*j^3*i^3.
a(n) = n^2 * (n + 1)^2 * (n - 1) * (n - 2) * (35*n^6 + 5*n^5 - 237*n^4 - 77*n^3 + 502*n^2 + 148*n -336)/13440.
a(n) = binomial(n+1,4)*binomial(n+1,2)*(35*n^6 + 5*n^5 - 237*n^4 - 77*n^3 + 502*n^2 + 148*n -336)/280.

A354021 a(n) = Sum_{1 <= i < j < k < m <= n} (m*k*j*i)^2.

Original entry on oeis.org

0, 0, 0, 0, 576, 21076, 296296, 2475473, 14739153, 68943381, 268880381, 909450751, 2742417535, 7522650135, 19058554515, 45123156390, 100771975590, 213877057086, 434042943246, 846542846578, 1593528150578
Offset: 0

Author

Roudy El Haddad, May 14 2022

Keywords

Comments

a(n) is the sum of all products of four distinct squares of positive integers up to n, i.e., the sum of all products of four distinct elements from the set of squares {1^2, ..., n^2}.

Crossrefs

Cf. A353021 (for nondistinct squares).
Cf. A000290 (squares), A000330 (sum of squares), A000596 (for two squares), A000597 (for three squares).
Cf. A001298 (for power 1).

Programs

  • PARI
    {a(n) = n*(n + 1)*(n - 1)*(n - 2)*(n - 3)*(2*n + 1)*(2*n - 1)*(2*n - 3)*(2*n - 5)*(5*n + 7)*(35*n^2 + 98*n + 72)/5443200};

Formula

a(n) = Sum_{m=4..n} Sum_{k=3..m-1} Sum_{j=2..k-1} Sum_{i=1..j-1} (m*k*j*i)^2.
a(n) = n*(n+1)*(n-1)*(n-2)*(n-3)*(2*n + 1)*(2*n - 1)*(2*n - 3)*(2*n - 5)*(5*n + 7)*(35*n^2 + 98*n + 72)/5443200.
a(n) = binomial(2*n+2,9)*(5*n + 7)*(35*n^2 + 98*n + 72)/(5!*4).

A352979 a(n) = Sum_{k=1..n} Sum_{j=1..k} Sum_{i=1..j} (k*j*i)^3.

Original entry on oeis.org

0, 1, 585, 28800, 505280, 4951530, 33209946, 170320080, 714724560, 2566030995, 8130545995, 23253835176, 61054704360, 149085989780, 342048076020, 743408003520, 1540821690816, 3062326169925, 5862986735085, 10855192630480, 19500255870480
Offset: 0

Author

Roudy El Haddad, Apr 13 2022

Keywords

Comments

a(n) is the sum of all products of three cubes of positive integers up to n, i.e., the sum of all products of three elements from the set of cubes {1^3, ..., n^3}.

References

  • El Haddad, R. (2022). A generalization of multiple zeta value. Part 1: Recurrent sums. Notes on Number Theory and Discrete Mathematics, 28(2), 167-199, DOI: 10.7546/nntdm.2022.28.2.167-199.

Crossrefs

Cf. A352980 (for distinct cubes).
Cf. A001297 (for power 1), A351105 (for squares).
Cf. A000578 (cubes), A000537 (sum of first n cubes), A346642 (order 2).

Programs

  • PARI
    {a(n) = n^2 * (n + 1)^2 * (n + 2) * (n + 3) * (35*n^6 + 205*n^5 + 263*n^4 - 221*n^3 - 214*n^2 + 324*n - 112)/13440};
    
  • Python
    def A352979(n): return n**2*(n*(n*(n*(n*(n*(n*(n*(n*(n*(35*n + 450) + 2293) + 5700) + 6405) + 770) - 3661) - 240) + 2320) + 40) - 672)//13440 # Chai Wah Wu, May 14 2022

Formula

a(n) = n^2 * (n + 1)^2 * (n + 2) * (n + 3) * (35*n^6 + 205*n^5 + 263*n^4 - 221*n^3 - 214*n^2 + 324*n - 112)/13440.
a(n) = binomial(n+3,4)*binomial(n+1,2)*(35*n^6 + 205*n^5 + 263*n^4 - 221*n^3 - 214*n^2 + 324*n - 112)/280.

A353021 a(n) = Sum_{l=1..n} Sum_{k=1..l} Sum_{j=1..k} Sum_{i=1..j} (l*k*j*i)^2.

Original entry on oeis.org

0, 1, 341, 13013, 196053, 1733303, 10787231, 52253971, 209609235, 725520510, 2230238010, 6217887390, 15973440990, 38276304066, 86383520146, 185042663146, 378620563178, 743881306623, 1409531082531, 2585397711611, 4605062303611
Offset: 0

Author

Roudy El Haddad, Apr 17 2022

Keywords

Comments

a(n) is the sum of all products of four squares of positive integers up to n, i.e., the sum of all products of four elements from the set of squares {1^2, ..., n^2}.

Crossrefs

Cf. A354021 (for distinct squares).
Cf. A000290 (squares), A000330 (sum of squares), A060493 (for two squares), A351105 (for three squares).
Cf. A000915 (for power 1).

Programs

  • PARI
    {a(n) = n*(n + 1)*(n + 2)*(n + 3)*(n + 4)*(2*n + 1)*(2*n + 3)*(2*n + 5)*(2*n + 7)*(5*n - 2)*(35*n^2 - 28*n + 9)/5443200};
    
  • Python
    def A353021(n): return n*(n*(n*(n*(n*(n*(n*(n*(8*n*(n*(70*n*(5*n + 84) + 40417) + 144720) + 2238855) + 2050020) + 207158) - 810600) - 58505) + 322740) + 7956) - 45360)//5443200 # Chai Wah Wu, May 14 2022

Formula

a(n) = n*(n + 1)*(n + 2)*(n + 3)*(n + 4)*(2*n + 1)*(2*n + 3)*(2*n + 5)*(2*n + 7)*(5*n - 2)*(35*n^2 - 28*n + 9)/5443200.
a(n) = binomial(2*n+8,9)*(5*n - 2)*(35*n^2 - 28*n + 9)/(5!*4).

A351864 Numerator of zeta({6}_n)/Pi^(6n).

Original entry on oeis.org

1, 1, 4, 2, 4, 1, 4, 4, 4, 4, 16, 2, 4, 2, 8, 8, 4, 4, 16, 8, 16, 1, 4, 4, 4, 4, 16, 4, 8, 4, 16, 16, 4, 4, 16, 8, 16, 4, 16, 16, 16, 16, 64, 2, 4, 2, 8, 8, 4, 4, 16, 8, 16, 2, 8, 8, 8, 8, 32, 8, 16, 8, 32, 32, 4, 4, 16, 8, 16, 4, 16
Offset: 0

Author

Roudy El Haddad, Feb 22 2022

Keywords

Comments

({6}_n) is standard notation for multiple zeta values. It represents (6, ..., 6) where the multiplicity of 6 is n.

Crossrefs

Cf. A351806 (denominators).

Programs

  • Mathematica
    a[n_] := Numerator[6*2^(6*n)/(6*n + 3)!]; Array[a, 71, 0]
  • PARI
    a(n) = 1 << (hammingweight(3*n+1) - 1);

Formula

a(n) = numerator(6*2^(6*n)/(6*n + 3)!).
a(n) = 2^(A000120(3*n + 1) - 1).
a(n) = 2^A240883(n).

A351805 a(n) = Sum_{1 <= i < j <= n} j^5*i^5.

Original entry on oeis.org

0, 0, 32, 8051, 290675, 4353175, 38761975, 243824182, 1194358326, 4842169350, 16924669350, 52488756425, 147511725257, 381689190701, 920589376525, 2089893985900, 4500779925100, 9254143113132, 18262909865676, 34746798604575, 63973358604575, 114343801467875
Offset: 0

Author

Roudy El Haddad, Feb 19 2022

Keywords

Comments

a(n) is the sum of all products of two distinct elements from the set {1^5, ..., n^5}.

Crossrefs

Cf. A000217 (for power 0), A000914 (for power 1), A000596 (for squares), A347107 (for cubes), (for fourth powers).
Cf. A000584 (fifth powers), A000539 (sum of fifth powers).

Programs

  • PARI
    {a(n) = n*(n-1)*(n+1)*(44*n^9+120*n^8-132*n^7-540*n^6+99*n^5+912*n^4-11*n^3-672*n^2+120)/3168};

Formula

a(n) = Sum_{j=2..n} Sum_{i=1..j-1} j^5*i^5.
a(n) = n*(n - 1)*(n + 1)*(44*n^9 + 120*n^8 - 132*n^7 - 540*n^6 + 99*n^5 + 912*n^4 - 11*n^3 - 672*n^2 + 120)/3168.
G.f.: -x^2*(x^9 +1044*x^8 +54462*x^7 +595860*x^6 +2048388*x^5 +2563644*x^4 +1193226*x^3 +188508*x^2 +7635*x +32)/(x-1)^13. - Alois P. Heinz, Feb 19 2022

A351806 Denominator of zeta({6}_n)/Pi^(6*n).

Original entry on oeis.org

1, 945, 212837625, 64965492466875, 432684797065192546875, 1347828286825972065254765625, 197885500589205605585596463448046875, 18132629348577543860598956218936672646484375, 3673787208165374996876652878250276546299488037109375
Offset: 0

Author

Roudy El Haddad, Feb 19 2022

Keywords

Comments

({6}_n) is standard notation for multiple zeta values. It represents (6, ..., 6) where the multiplicity of 6 is n.

Crossrefs

Cf. A351864 (numerators).
Cf. A002432 (denominators of zeta(2*n)/Pi^(2*n)).
Cf. A013664 (zeta(6)).
Cf. A103345.

Programs

  • Mathematica
    a[n_] := Denominator[6*2^(6*n)/(6*n + 3)!]; Array[a, 9, 0] (* Amiram Eldar, Feb 19 2022 *)
  • PARI
    a(n) = denominator(6*2^(6*n)/(6*n + 3)!); \\ Michel Marcus, Feb 22 2022

Formula

a(n) = denominator(6*2^(6*n)/(6*n + 3)!).

A351770 a(n) = Sum_{j=1..n} Sum_{i=1..j} (i*j)^5.

Original entry on oeis.org

0, 1, 1057, 68125, 1399325, 15227450, 110102426, 597639882, 2621915850, 9756511275, 31839011275, 93340522951, 250280856007, 622316813300, 1450471654100, 3196426654100, 6706824221076, 13476181309557, 26055415288725, 48670370285425, 88136930285425, 155187254126926
Offset: 0

Author

Roudy El Haddad, Feb 18 2022

Keywords

Comments

a(n) is the sum of all products of two elements from the set {1^5, ..., n^5}.

Crossrefs

Cf. A001296 (for power 1), A060493 (for squares), A346642 (for cubes), A351766 (for fourth powers).
Cf. A000584 (fifth powers), A000539 (sum of fifth powers).

Programs

  • Maple
    seq(n*(n+1)*(n+2)*(44*n^9+276*n^8+492*n^7-48*n^6-609*n^5+207*n^4+487*n^3-291*n^2-90*n+60)/3168,
    n=0..30);# Robert Israel, Feb 18 2022
  • PARI
    {a(n) = n*(n+1)*(n+2)*(44*n^9+276*n^8+492*n^7-48*n^6-609*n^5+207*n^4+487*n^3-291*n^2-90*n+60)/3168};
    
  • PARI
    a(n) = sum(j=1, n, sum(i=1, j, i^5*j^5));

Formula

a(n) = n*(n+1)*(n+2)*(44*n^9 + 276*n^8 + 492*n^7 - 48*n^6 - 609*n^5 + 207*n^4 + 487*n^3 - 291*n^2 - 90*n + 60)/3168.
G.f.: x*(1 + 1044*x + 54462*x^2 + 595860*x^3 + 2048388*x^4 + 2563644*x^5 + 1193226*x^6 + 188508*x^7 + 7635*x^8 + 32*x^9)/(1-x)^13. - Robert Israel, Feb 18 2022

A351760 a(n) = Sum_{1 <= i < j <= n} (i*j)^4.

Original entry on oeis.org

0, 0, 16, 1393, 26481, 247731, 1516515, 6978790, 26131686, 83684778, 237014778, 607915231, 1436816095, 3170754405, 6600189141, 13064343516, 24750198748, 45116627556, 79482515700, 135826148445, 225852708445, 366397514791, 581244702423, 903454469346, 1378306878690, 2066986566190
Offset: 0

Author

Roudy El Haddad, Feb 18 2022

Keywords

Comments

a(n) is the sum of all products of two distinct elements from the set {1^4, ..., n^4}.

Crossrefs

Cf. A000217 (for power 0), A000914 (for power 1), A000596 (for squares), A347107 (for cubes).
Cf. A000583 (fourth powers), A000538 (sum of fourth powers).

Programs

  • PARI
    {a(n) = n*(n-1)*(n+1)*(2*n-1)*(2*n+1)*(9*n^5+20*n^4-15*n^3-50*n^2+n+30)/1800};
    
  • PARI
    a(n) = sum(j=2, n, sum(i=1, j-1, i^4*j^4));
    
  • Python
    def A351760(n): return n*(n*(n*(n*(n*(n*(n*(n*(n*(9*n+20<<2)-105)-300)+88)+390)-20)-200)+1)+30)//1800 # Chai Wah Wu, Oct 03 2024

Formula

a(n) = Sum_{j=2..n} Sum_{i=1..j-1} j^4*i^4.
a(n) = n*(n - 1)*(n + 1)*(2*n - 1)*(2*n + 1)*(9*n^5 + 20*n^4 - 15*n^3 - 50*n^2 + n + 30)/1800.
a(n) = binomial(2*n+2, 5)*(9*n^5 + 20*n^4 - 15*n^3 - 50*n^2 + n + 30)/5!.
G.f.: x^2*(16 + 1217*x + 12038*x^2 + 30415*x^3 + 23364*x^4 + 5263*x^5 + 262*x^6 + x^7)/(1 - x)^11. - Stefano Spezia, Feb 18 2022

A351766 a(n) = Sum_{j=1..n} Sum_{i=1..j} (i*j)^4.

Original entry on oeis.org

0, 1, 273, 8211, 98835, 710710, 3659110, 14886186, 50816298, 151416111, 404746111, 990005445, 2248888005, 4798557036, 9703780828, 18730825828, 34711648356, 62053834605, 107439683325, 180766879111, 296393439111, 474761104818, 744484165986, 1145004918190, 1729932641710, 2571200219835
Offset: 0

Author

Roudy El Haddad, Feb 18 2022

Keywords

Comments

a(n) is the sum of all products of two elements from the set {1^4, ..., n^4}.

Crossrefs

Cf. A000217 (for power 0), A001296 (for power 1), A060493 (for squares), A346642 (for cubes).
Cf. A000583 (fourth powers), A000538 (sum of fourth powers).

Programs

  • PARI
    {a(n) = n*(n+1)*(n+2)*(2*n+1)*(2*n+3)*(9*n^5+25*n^4-5*n^3-25*n^2+21*n-5)/1800};
    
  • PARI
    a(n) = sum(j=1, n, sum(i=1, j, i^4*j^4));

Formula

a(n) = n*(n + 1)*(n + 2)*(2*n + 1)*(2*n + 3)*(9*n^5 + 25*n^4 - 5*n^3 - 25*n^2 + 21*n - 5)/1800.
a(n) = binomial(2*n+4,5) * (9*n^5 + 25*n^4 - 5*n^3 - 25*n^2 + 21*n - 5)/5!.
G.f.: x*(16*x^7 + 1217*x^6 + 12038*x^5 + 30415*x^4 + 23364*x^3 + 5263*x^2 + 262*x + 1)/(1 - x)^11. - Alois P. Heinz, Feb 18 2022