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 10 results.

A321798 G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^4).

Original entry on oeis.org

1, 1, 5, 23, 117, 636, 3607, 21106, 126489, 772468, 4789844, 30075937, 190851839, 1222000222, 7885041530, 51222338580, 334720178969, 2198755865424, 14511029102232, 96169424666028, 639757737711300, 4270520564506069, 28595671605541357, 192025292117465445, 1292866976587651519
Offset: 0

Views

Author

Ludovic Schwob, Nov 19 2018

Keywords

Crossrefs

Programs

  • GAP
    List([0..25],n->Sum([0..n],k->Binomial(n,k)/(n-k+1)*Binomial(n+3*k-1,n-k))); # Muniru A Asiru, Nov 24 2018
  • Mathematica
    a[n_] := Sum[Binomial[n, k] * Binomial[n + 3k - 1, n - k]/(n - k + 1), {k, 0,
    n}]; Array[a, 20, 0] (* Amiram Eldar, Nov 19 2018 *)
  • PARI
    a(n) = sum(k=0, n, binomial(n,k)*binomial(n+3*k-1, n-k)/(n-k+1)); \\ Michel Marcus, Nov 19 2018
    

Formula

a(n) = Sum_{k=0..n} (C(n,k)/(n-k+1)) * C(n+3*k-1,n-k).
a(n) ~ sqrt((1 - r*s)*(1 + 3*r*s)/(8*Pi*(8*s - 3))) / (n^(3/2) * r^(n+1)), where r = 0.139684805934917057093949761392656080860096066578... and s = 1.76437708701490464570032194388560298744432681226... are real roots of the system of equations s*(1 - r/(1 - r*s)^4) = 1, 4*r^2*s^2 = (1 - r*s)^5. - Vaclav Kotesovec, Nov 21 2018

A161798 G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^3)^2.

Original entry on oeis.org

1, 2, 9, 46, 262, 1590, 10081, 65986, 442518, 3024772, 20996141, 147603198, 1048747751, 7519252606, 54332565330, 395264527626, 2892666314150, 21281120904168, 157299607827727, 1167582500757800, 8699515577902203
Offset: 0

Views

Author

Paul D. Hanna, Jun 19 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[2*n-k+1,k]/(n-k+1)*Binomial[n+2*k-1,n-k],{k,0,n}],{n,0,20}] (* Vaclav Kotesovec, Sep 18 2013 *)
  • PARI
    {a(n,m=1)=sum(k=0,n,binomial(2*n-k+m,k)*m/(n-k+m)*binomial(n+2*k-1,n-k))}

Formula

a(n) = Sum_{k=0..n} C(2*n-k+1,k)/(n-k+1) * C(n+2*k-1,n-k).
Let A(x)^m = Sum_{n>=0} a(n,m)*x^n then
a(n,m) = Sum_{k=0..n} C(2*n-k+m,k)*m/(n-k+m) * C(n+2*k-1,n-k).
a(n) ~ c*d^n/(sqrt(Pi)*n^(3/2)), where d = 8.01957328653868383... is the root of the equation 3125 + 22356*d - 162432*d^2 - 361584*d^3 - 326592*d^4 + 46656*d^5 = 0 and c = 1.216730444416766043545857948227854793382399566... - Vaclav Kotesovec, Sep 18 2013

A321799 G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^5).

Original entry on oeis.org

1, 1, 6, 31, 176, 1071, 6797, 44493, 298279, 2037550, 14131441, 99244564, 704360703, 5043969503, 36399930179, 264451303466, 1932650461883, 14198082537190, 104792195449688, 776681663951998, 5778226417888171, 43135097969972931, 323012620411650708, 2425745980876575899, 18264470545275495152
Offset: 0

Views

Author

Ludovic Schwob, Nov 19 2018

Keywords

Crossrefs

Programs

  • GAP
    List([0..25],n->Sum([0..n],k->Binomial(n,k)/(n-k+1)*Binomial(n+4*k-1,n-k))); # Muniru A Asiru, Nov 24 2018
    
  • Magma
    [1] cat [&+[(Binomial(n,k)/(n-k+1)) * Binomial(n+4*k-1,n-k):  k in [0..n]]: n in [1.. 25]]; // Vincenzo Librandi, Dec 08 2018
    
  • Maple
    eq:= a - 1/(1-x/(1-x*a)^5):
    S:= series(RootOf(numer(eq),a),x,31):
    seq(coeff(S,x,j),j=0..30); # Robert Israel, Dec 10 2018
  • Mathematica
    a[n_]:=Sum[ Binomial[n,k]/(n-k+1)*Binomial[n+4*k-1,n-k], {k,0,n}]; Array[a, 20, 0] (* Stefano Spezia, Nov 19 2018 *)
    A[] = 0; Do[A[x] = 1/(1-x/(1-x*A[x])^5)+O[x]^25, {25}];
    CoefficientList[A[x], x] (* Jean-François Alcover, Dec 30 2018 *)
  • PARI
    a(n) = sum(k=0, n, binomial(n,k)*binomial(n+4*k-1, n-k)/(n-k+1)); \\ Michel Marcus, Nov 19 2018
    
  • Sage
    [sum(binomial(n,k)*binomial(n+4*k-1,n-k)/(n-k+1) for k in (0..n)) for n in range(25)] # G. C. Greubel, Dec 14 2018

Formula

a(n) = Sum_{k=0..n} (C(n,k)/(n-k+1)) * C(n+4*k-1,n-k).
a(n) ~ sqrt((1 - r*s)*(1 + 4*r*s) / (5*Pi*(5*s - 2))) / (2 * n^(3/2) * r^(n+1)), where r = 0.124910212976238209867004924637837518925706044646... and s = 1.72708330560542094133450070142549940430523638921... are real roots of the system of equations s*(1 - r/(1 - r*s)^5) = 1, 5*r^2*s^2 = (1 - r*s)^6. - Vaclav Kotesovec, Nov 21 2018

A365113 G.f. satisfies A(x) = 1 + x / (1 - x*A(x))^3.

Original entry on oeis.org

1, 1, 3, 9, 31, 114, 438, 1739, 7077, 29364, 123756, 528324, 2279868, 9928679, 43580301, 192601419, 856317717, 3827501985, 17188943523, 77521747638, 350959738842, 1594390493067, 7266093316649, 33209221327752, 152182572790008, 699083290518817, 3218624408121555
Offset: 0

Views

Author

Seiichi Manyama, Aug 22 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n, s=3) = sum(k=0, n, binomial(n-k+1, k)*binomial(n+(s-1)*k-1, n-k)/(n-k+1));

Formula

If g.f. satisfies A(x) = 1 + x/(1 - x*A(x))^s, then a(n) = Sum_{k=0..n} binomial(n-k+1,k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).

A365086 G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x))^3.

Original entry on oeis.org

1, 1, -2, -2, 15, -4, -122, 204, 903, -3374, -4635, 43539, -13233, -475123, 873392, 4244591, -16906773, -24952174, 244162840, -74520792, -2901715074, 5483226036, 27740164293, -112969486284, -172903931727, 1714556657881, -513739179725, -21235809823325
Offset: 0

Views

Author

Seiichi Manyama, Aug 21 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, (-1)^(n-k)*binomial(n, k)*binomial(n+2*k-1, n-k)/(n-k+1));

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(n+2*k-1,n-k) / (n-k+1).

A161799 G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^2)^3.

Original entry on oeis.org

1, 3, 12, 61, 345, 2085, 13182, 86106, 576543, 3936029, 27294390, 191722887, 1361291244, 9754412169, 70447946556, 512278417176, 3747570671685, 27561220671408, 203657352324178, 1511270129552163, 11257532921742528
Offset: 0

Views

Author

Paul D. Hanna, Jun 19 2009

Keywords

Crossrefs

Programs

  • Maple
    A161799 := proc(n)
        local s,t ;
        s := 2 ;
        t := 3;
        add( binomial(t*n-(t-1)*(k-1),k) * binomial(n+(s-1)*k-1,n-k) /(n-k+1) ,k=0..n) ;
    end proc:
    seq(A161799(n),n=0..40) ; # R. J. Mathar, May 12 2022
  • Mathematica
    Table[Sum[Binomial[3*n-2*k+2,k]/(n-k+1)*Binomial[n+k-1,n-k],{k,0,n}],{n,0,20}] (* Vaclav Kotesovec, Sep 18 2013 *)
  • PARI
    {a(n,m=1)=sum(k=0,n,binomial(3*n-2*k+3*m-1,k)*m/(n-k+m)*binomial(n+k-1,n-k))}

Formula

a(n) = Sum_{k=0..n} C(3*n-2*k+2,k)/(n-k+1) * C(n+k-1,n-k).
Let A(x)^m = Sum_{n>=0} a(n,m)*x^n then
a(n,m) = Sum_{k=0..n} C(3*n-2*k+3*m-1,k)*m/(n-k+m) * C(n+k-1,n-k).
a(n) ~ c*d^n/(sqrt(Pi)*n^(3/2)), where d = 8.01957328653868383... is the root of the equation 3125 + 22356*d - 162432*d^2 - 361584*d^3 - 326592*d^4 + 46656*d^5 = 0 and c = 1.56703431595354192843152170651865561188... - Vaclav Kotesovec, Sep 18 2013

A367233 G.f. satisfies A(x) = 1 + x*A(x)^3 / (1 - x*A(x))^3.

Original entry on oeis.org

1, 1, 6, 39, 284, 2223, 18267, 155445, 1358073, 12111306, 109802183, 1009001571, 9376972698, 87978198364, 832223905371, 7928413841673, 76002832317437, 732578811761670, 7095717550127526, 69029297500888522, 674181392461483212, 6607910786529613248
Offset: 0

Views

Author

Seiichi Manyama, Nov 11 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n, s=3, t=3, u=1) = sum(k=0, n, binomial(t*k+u*(n-k)+1, k)*binomial(n+(s-1)*k-1, n-k)/(t*k+u*(n-k)+1));

Formula

If g.f. satisfies A(x) = 1 + x*A(x)^t / (1 - x*A(x)^u)^s, then a(n) = Sum_{k=0..n} binomial(t*k+u*(n-k)+1,k) * binomial(n+(s-1)*k-1,n-k) / (t*k+u*(n-k)+1).

A349022 G.f. satisfies A(x) = 1/(1 - x/(1 - x*A(x))^3)^4.

Original entry on oeis.org

1, 4, 22, 152, 1161, 9460, 80550, 708172, 6379368, 58576168, 546215580, 5158542152, 49239812893, 474285453628, 4604149947276, 44999181550032, 442430807369519, 4372944634271688, 43425156714959956, 433049078716727332, 4334925824762251939
Offset: 0

Views

Author

Seiichi Manyama, Nov 06 2021

Keywords

Crossrefs

Programs

  • Maple
    A349022 := proc(n)
        add(binomial(4*n-3*(k-1),k)*binomial(n+2*k-1,n-k)/(n-k+1),k=0..n) ;
    end proc:
    seq(A349022(n),n=0..40) ; # R. J. Mathar, Jan 25 2023
  • PARI
    a(n, s=3, t=4) = sum(k=0, n, binomial(t*n-(t-1)*(k-1), k)*binomial(n+(s-1)*k-1, n-k)/(n-k+1));

Formula

If g.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*n-(t-1)*(k-1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).

A365135 G.f. satisfies A(x) = (1 + x*A(x)/(1 - x*A(x))^3)^2.

Original entry on oeis.org

1, 2, 11, 68, 467, 3418, 26133, 206264, 1667908, 13746476, 115050074, 975180582, 8354044986, 72215867960, 629139381448, 5518236646614, 48689379017014, 431868759238498, 3848616161600778, 34441553184113542, 309390614528633311, 2788841905397090626
Offset: 0

Views

Author

Seiichi Manyama, Aug 23 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n, s=3, t=2) = sum(k=0, n, binomial(t*(n+1), k)*binomial(n+(s-1)*k-1, n-k))/(n+1);

Formula

If g.f. satisfies A(x) = (1 + x*A(x)/(1 - x*A(x))^s)^t, then a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(t*(n+1),k) * binomial(n+(s-1)*k-1,n-k).

A365136 G.f. satisfies A(x) = (1 + x*A(x)/(1 - x*A(x))^3)^3.

Original entry on oeis.org

1, 3, 21, 172, 1563, 15141, 153240, 1601160, 17140686, 187026210, 2072333697, 23255417925, 263757940688, 3018654757212, 34817822871933, 404324843585061, 4723248984803013, 55467143334798210, 654435356605769574, 7753961433310798095, 92220463998917459652
Offset: 0

Views

Author

Seiichi Manyama, Aug 23 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n, s=3, t=3) = sum(k=0, n, binomial(t*(n+1), k)*binomial(n+(s-1)*k-1, n-k))/(n+1);

Formula

If g.f. satisfies A(x) = (1 + x*A(x)/(1 - x*A(x))^s)^t, then a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(t*(n+1),k) * binomial(n+(s-1)*k-1,n-k).
Showing 1-10 of 10 results.