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.

Previous Showing 51-59 of 59 results.

A127778 Triangle T(n,k) = A002411(k) read by rows.

Original entry on oeis.org

1, 1, 6, 1, 6, 18, 1, 6, 18, 40, 1, 6, 18, 40, 75, 1, 6, 18, 40, 75, 126, 1, 6, 18, 40, 75, 126, 196, 1, 6, 18, 40, 75, 126, 196, 288
Offset: 1

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Author

Gary W. Adamson, Jan 28 2007

Keywords

Examples

			First few rows of the triangle are:
1;
1, 6;
1, 6, 18;
1, 6, 18, 40;
1, 6, 18, 40, 75;
...
		

Crossrefs

Cf. A002411, A001296 (row sums), A127773, A002260, A127777.

Formula

Equals the matrix product A002260 * A127773 as infinite lower triangular matrices.

A151510 The triangle in A151338 read by rows upwards.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 6, 7, 1, 0, 1, 10, 25, 15, 1, 0, 1, 15, 65, 90, 31, 0, 0, 1, 21, 140, 350, 301, 56, 0, 0, 1, 28, 266, 1050, 1701, 938, 91, 0, 0, 1, 36, 462, 2646, 6951, 7686, 2737, 126, 0, 0, 1, 45, 750, 5880, 22827, 42315, 32725, 7455, 126, 0, 0
Offset: 0

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Author

N. J. A. Sloane, May 14 2009

Keywords

Comments

Columns 1-5 are A000012, A000217, A001296, A001297, and A001298. - Nathaniel Johnston, Apr 30 2011

Examples

			Triangle begins:
1
1 0
1 1  0
1 3  1   0
1 6  7   1    0
1 10 25  15   1    0
1 15 65  90   31   0   0
1 21 140 350  301  56  0  0
1 28 266 1050 1701 938 91 0 0
...
		

Extensions

Extended by Nathaniel Johnston, Apr 30 2011

A259455 n Sum_n Sum_n Sum_n.

Original entry on oeis.org

1, 30, 270, 1400, 5250, 15876, 41160, 95040, 200475, 393250, 726726, 1277640, 2153060, 3498600, 5508000, 8434176, 12601845, 18421830, 26407150, 37191000, 51546726, 70409900, 94902600, 126360000, 166359375, 216751626, 279695430, 357694120, 453635400, 570834000
Offset: 1

Views

Author

N. J. A. Sloane, Jun 30 2015

Keywords

Comments

See the reference for an explanation of the rather cryptic definition.

Crossrefs

This is the seventh sequence in the sequence A000027, A000217, A002411, A001296, A108650, A001297, ...

Programs

  • Maple
    a:= n-> n^3*(n+3)*(n+2)*(n+1)^2/48:
    seq(a(n), n=1..40);  # Alois P. Heinz, Jul 04 2015

Formula

From Alois P. Heinz, Jul 04 2015: (Start)
G.f.: (24*x^3+58*x^2+22*x+1)*x/(x-1)^8.
a(n) = n^3*(n+3)*(n+2)*(n+1)^2/48.
a(n) = n*Stirling2(n+3,n). (End)

Extensions

More terms from Alois P. Heinz, Jul 04 2015

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

Views

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

A382225 Triangle read by rows: T(n,k) = Sum_{i=k..n} C(i-1,i-k)*C(i,k).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 6, 7, 1, 1, 10, 25, 13, 1, 1, 15, 65, 73, 21, 1, 1, 21, 140, 273, 171, 31, 1, 1, 28, 266, 798, 871, 346, 43, 1, 1, 36, 462, 1974, 3321, 2306, 631, 57, 1, 1, 45, 750, 4326, 10377, 11126, 5335, 1065, 73, 1, 1, 55, 1155, 8646, 28017, 42878, 31795, 11145, 1693, 91, 1
Offset: 0

Views

Author

Vladimir Kruchinin, Mar 19 2025

Keywords

Comments

Triangle T(n,k) of minors of the main diagonal of Pascal's matrix, n -size matrix, k - number of element of diagonal.

Examples

			Triangle starts:
  1;
  1,  1;
  1,  3,   1;
  1,  6,   7,   1;
  1, 10,  25,  13,   1;
  1, 15,  65,  73,  21,  1;
  1, 21, 140, 273, 171, 31, 1;
  ...
		

Crossrefs

Columns k=0-3 give: A000012, A000217, A001296(n-1) for n>=1, A107963(n-3) for n>=3.
Row sums give A024718.
T(n+1,n) gives A002061(n+1).

Programs

  • Maple
    T:= proc(n, k) option remember; `if`(n<0, 0,
          T(n-1, k)+binomial(n-1, k-1)*binomial(n, k))
        end:
    seq(seq(T(n, k), k=0..n), n=0..10);  # Alois P. Heinz, Mar 20 2025
  • Mathematica
    A382225[n_, k_] := A382225[n, k] = If[k == n, 1, A382225[n-1, k] + Binomial[n-1, k-1]*Binomial[n, k]];
    Table[A382225[n, k], {n, 0, 10}, {k, 0, n}] (* Paolo Xausa, Mar 22 2025 *)
  • Maxima
    h[i,j]:=binomial(i+j-3,i-1);
    for n:1 thru 7 do
        if n=1 then print([1])
        else (M:genmatrix(h,n,n),
              print(makelist(determinant(minor(M,k,k)),k,1,n))
             );

Formula

G.f.: 1/(1-x) * ((1-x*(1-y))/(2*(sqrt((1-x*(1+y))^2-4*x^2*y)))+1/2).
T(n,k) = T(n-1,k)+C(n-1,k-1)*C(n,k).

A273528 Triangle T(n,m) (n >= 1, 0 <= m < n) giving coefficients of (n-1)! P_n, where P_n is the polynomial formula for row n of A213086.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 3, 2, 0, 2, 9, 10, 3, 0, 2, 25, 50, 35, 8, 0, -12, 86, 270, 260, 102, 14, 0, -120, 140, 1344, 2030, 1260, 350, 36, 0, -1248, -1016, 7336, 15862, 13048, 5236, 1024, 78, 0, -9216, -22464, 28528, 124488, 139776, 76104, 22152, 3312, 200, 0, -90720, -322344, 1860, 1036990, 1514205, 1018563, 379890, 80760, 9165, 431
Offset: 1

Views

Author

Jean-François Alcover, May 24 2016

Keywords

Examples

			Row T(5) = {0, 2, 9, 10, 3}, so P_5(k) = (1/4!)(2k + 9k^2 + 10k^3 + 3k^4), which gives 1, 7, 25, 65, 140, 266, ..., that is A001296 (row 5 of A213086), for k >=1.
Triangle begins:
{1},
{0, 1},
{0, 1, 1},
{0, 1, 3, 2},
{0, 2, 9, 10, 3},
{0, 2, 25, 50, 35, 8},
{0, -12, 86, 270, 260, 102, 14},
...
		

Crossrefs

Formula

The first formulas (stripped of factorials) :
1,
k,
k + k^2,
k + 3 k^2 + 2 k^3,
2 k + 9 k^2 + 10 k^3 + 3 k^4,
2 k + 25 k^2 + 50 k^3 + 35 k^4 + 8 k^5,
-12 k + 86 k^2 + 270 k^3 + 260 k^4 + 102 k^5 + 14 k^6,
-120 k + 140 k^2 + 1344 k^3 + 2030 k^4 + 1260 k^5 + 350 k^6 + 36 k^7,
...

A301972 a(n) = n*(n^2 - 2*n + 4)*binomial(2*n,n)/((n + 1)*(n + 2)).

Original entry on oeis.org

0, 1, 4, 21, 112, 570, 2772, 13013, 59488, 266526, 1175720, 5123426, 22108704, 94645460, 402503220, 1702300725, 7165821120, 30043474230, 125523450360, 522857438070, 2172127120800, 9002522512620, 37233403401480, 153704429299746, 633442159732032, 2606543487445100, 10710790748646352, 43957192722175908
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 29 2018

Keywords

Comments

For n > 2, a(n) is the n-th term of the main diagonal of iterated partial sums array of n-gonal numbers (in other words, a(n) is the n-th (n+2)-dimensional n-gonal number, see also example).

Examples

			For n = 5 we have:
----------------------------
0   1    2    3     4    [5]
----------------------------
0,  1,   5,  12,   22,   35,  ... A000326 (pentagonal numbers)
0,  1,   6,  18,   40,   75,  ... A002411 (pentagonal pyramidal numbers)
0,  1,   7,  25,   65,  140,  ... A001296 (4-dimensional pyramidal numbers)
0,  1,   8,  33,   98,  238,  ... A051836 (partial sums of A001296)
0,  1,   9,  42,  140,  378,  ... A051923 (partial sums of A051836)
0,  1,  10,  52,  192, [570], ... A050494 (partial sums of A051923)
----------------------------
therefore a(5) = 570.
		

Crossrefs

Programs

  • Mathematica
    Table[n (n^2 - 2 n + 4) Binomial[2 n, n]/((n + 1) (n + 2)), {n, 0, 27}]
    nmax = 27; CoefficientList[Series[(-4 + 31 x - 66 x^2 + 28 x^3 + (4 - 7 x) (1 - 4 x)^(3/2))/(2 x^2 (1 - 4 x)^(3/2)), {x, 0, nmax}], x]
    nmax = 27; CoefficientList[Series[Exp[2 x] (4 - x + 2 x^2) BesselI[1, 2 x]/x - 2 Exp[2 x] (2 - x) BesselI[0, 2 x], {x, 0, nmax}], x] Range[0, nmax]!
    Table[SeriesCoefficient[x (1 - 3 x + n x)/(1 - x)^(n + 3), {x, 0, n}], {n, 0, 27}]

Formula

O.g.f.: (-4 + 31*x - 66*x^2 + 28*x^3 + (4 - 7*x)*(1 - 4*x)^(3/2))/(2*x^2*(1 - 4*x)^(3/2)).
E.g.f.: exp(2*x)*(4 - x + 2*x^2)*BesselI(1,2*x)/x - 2*exp(2*x)*(2 - x)*BesselI(0,2*x).
a(n) = [x^n] x*(1 - 3*x + n*x)/(1 - x)^(n+3).
a(n) ~ 4^n*sqrt(n)/sqrt(Pi).
D-finite with recurrence: -(n+2)*(961*n-3215)*a(n) +4*(2081*n^2-4414*n-4668)*a(n-1) -28*(320*n-389)*(2*n-3)*a(n-2)=0. - R. J. Mathar, Jan 27 2020

A301973 a(n) = (n^2 - 3*n + 6)*binomial(n+2,3)/4.

Original entry on oeis.org

0, 1, 4, 15, 50, 140, 336, 714, 1380, 2475, 4180, 6721, 10374, 15470, 22400, 31620, 43656, 59109, 78660, 103075, 133210, 170016, 214544, 267950, 331500, 406575, 494676, 597429, 716590, 854050, 1011840, 1192136, 1397264, 1629705, 1892100, 2187255, 2518146, 2887924, 3299920, 3757650, 4264820
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 29 2018

Keywords

Comments

For n > 2, a(n) is the n-th term of the partial sums of n-gonal pyramidal numbers (in other words, a(n) is the n-th 4-dimensional n-gonal number).

Crossrefs

Programs

  • Mathematica
    Table[(n^2 - 3 n + 6) Binomial[n + 2, 3]/4, {n, 0, 40}]
    nmax = 40; CoefficientList[Series[x (1 - 2 x + 6 x^2)/(1 - x)^6, {x, 0, nmax}], x]
    nmax = 40; CoefficientList[Series[Exp[x] x (24 + 24 x + 24 x^2 + 10 x^3 + x^4)/24, {x, 0, nmax}], x] Range[0, nmax]!
    Table[SeriesCoefficient[x (1 - 3 x + n x)/(1 - x)^5, {x, 0, n}], {n, 0, 40}]
    LinearRecurrence[{6, -15, 20, -15, 6, -1}, {0, 1, 4, 15, 50, 140}, 41]

Formula

O.g.f.: x*(1 - 2*x + 6*x^2)/(1 - x)^6.
E.g.f.: exp(x)*x*(24 + 24*x + 24*x^2 + 10*x^3 + x^4)/24.
a(n) = [x^n] x*(1 - 3*x + n*x)/(1 - x)^5.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6).

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

Views

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
Previous Showing 51-59 of 59 results.