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 1-5 of 5 results.

A097191 G.f. A(x) has the property that the first (n+1) terms of A(x)^(n+1) form the n-th row polynomial R_n(y) of triangle A097190 and satisfy R_n(1/3) = 9^n for all n>=0.

Original entry on oeis.org

1, 12, 60, 90, -558, -2916, 2160, 61155, 137619, -767880, -4940676, 0, 95128668, 285386004, -974126979, -8413235910, -6504831279, 142312459626, 552074177142, -1081032363522, -13861905214518, -20792857821777, 204246531941697, 1012677253935633, -890531709052761
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Examples

			A(x) = 1 + 12*x + 60*x^2 + 90*x^3 - 558*x^4 - 2916*x^5 + 2160*x^6 +...
For n>=0, the first (n+1) coefficients of A(x)^(n+1) forms the
n-th row polynomial R_n(y) of triangle A097190:
A^1 = {1, _12,   60,    90,    -558,    -2916,       2160, ...}
A^2 = {1,  24, _264,  1620,    4644,    -8424,    -124524, ...}
A^3 = {1,  36,  612, _6318,   41526,   151956,     -16308, ...}
A^4 = {1,  48, 1104, 15912, _156744,  1061424,    4423032, ...}
A^5 = {1,  60, 1740, 32130,  417690, _3966732,   27243000, ...}
A^6 = {1,  72, 2520, 56700,  912492, 11027016, _101653164, ...}
These row polynomials satisfy: R_n(1/3) = 9^n:
9^1 = 1 + 24/3;
9^2 = 1 + 36/3 + 612/3^2;
9^3 = 1 + 48/3 + 1104/3^2 + 15912/3^3;
9^4 = 1 + 60/3 + 1740/3^2 + 32130/3^3 + 417690/3^4.
		

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( 27*x/(1-(1-3*x)^9) )); // G. C. Greubel, Sep 17 2019
    
  • Maple
    seq(coeff(series(27*x/(1-(1-3*x)^9), x, n+2), x, n), n = 0..30); # G. C. Greubel, Sep 17 2019
  • Mathematica
    CoefficientList[Series[27*x/(1-(1-3*x)^9), {x,0,30}], x] (* G. C. Greubel, Sep 17 2019 *)
  • PARI
    a(n)=polcoeff(27*x/(1-(1-3*x)^9)+x*O(x^n),n,x)
    
  • Sage
    def A097191_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P(27*x/(1-(1-3*x)^9)).list()
    A097191_list(30) # G. C. Greubel, Sep 17 2019

Formula

G.f.: A(x) = 27*x/(1-(1-3*x)^9).
G.f. satisfies: A(x) = G(x/A(x)) where G(x) = A(x*G(x)) is the g.f. of A097193.
a(18*n+11) = 0 for n>=0.

A097193 G.f. A(x) satisfies A097191(x*A(x)) = A(x) and so equals the ratio of the g.f.s of any two adjacent diagonals of triangle A097190.

Original entry on oeis.org

1, 12, 204, 3978, 83538, 1837836, 41745132, 970574319, 22970258883, 551286213192, 13381219902024, 327839887599588, 8095123378420596, 201221638263597672, 5030540956589941800, 126392341534322287725
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 20); Coefficients(R!( (1-(1-27*x)^(1/9))/(3*x) )); // G. C. Greubel, Sep 17 2019
    
  • Maple
    seq(coeff(series((1-(1-27*x)^(1/9))/(3*x), x, n+2), x, n), n = 0 ..20); # G. C. Greubel, Sep 17 2019
  • Mathematica
    CoefficientList[Series[(1-(1-27*x)^(1/9))/(3*x), {x, 0, 20}], x] (* Vaclav Kotesovec, Feb 12 2014 *)
  • PARI
    a(n)=polcoeff((1-(1-27*x+x^2*O(x^n))^(1/9))/(3*x),n,x)
    
  • Sage
    def A097193_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P((1-(1-27*x)^(1/9))/(3*x)).list()
    A097193_list(20) # G. C. Greubel, Sep 17 2019

Formula

G.f.: A(x) = (1-(1-27*x)^(1/9))/(3*x).
G.f.: A(x) = (1/x)*(series reversion of x/A097191(x)).
a(n) = A097192(n)/(n+1).
a(n) ~ 27^n / (Gamma(8/9) * n^(10/9)). - Vaclav Kotesovec, Feb 12 2014

A097192 Main diagonal of triangle A097190, in which the n-th row polynomial R_n(y) is formed from the initial (n+1) terms of g.f. A097191(y)^(n+1), where R_n(1/3) = 9^n for all n>=0.

Original entry on oeis.org

1, 24, 612, 15912, 417690, 11027016, 292215924, 7764594552, 206732329947, 5512862131920, 147193418922264, 3934078651195056, 105236603919467748, 2817102935690367408, 75458114348849127000, 2022277464549156603600
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 20); Coefficients(R!( 1/(1-27*x)^(8/9) )); // G. C. Greubel, Sep 17 2019
    
  • Maple
    seq(coeff(series(1/(1-27*x)^(8/9), x, n+1), x, n), n = 0 ..20); # G. C. Greubel, Sep 17 2019
  • Mathematica
    CoefficientList[Series[(1-27*x)^(-8/9), {x,0,20}], x] (* G. C. Greubel, Sep 17 2019 *)
  • PARI
    a(n)=polcoeff(1/(1-27*x+x*O(x^n))^(8/9),n,x)
    
  • Sage
    def A097192_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P(1/(1-27*x)^(8/9)).list()
    A097192_list(20) # G. C. Greubel, Sep 17 2019

Formula

G.f.: A(x) = 1/(1-27*x)^(8/9).
a(n) = (n+1)*A097193(n).
Conjecture: n*a(n) +3*(1-9*n)*a(n-1) = 0. - R. J. Mathar, Nov 16 2012

A097194 Row sums of triangle A097190, in which the n-th row polynomial R_n(y) is formed from the initial (n+1) terms of g.f. A097191(y)^(n+1), where R_n(1/3) = 9^n for all n>=0.

Original entry on oeis.org

1, 25, 649, 17065, 451621, 11998801, 319623445, 8530126057, 227974775239, 6099550226965, 163340461497907, 4377292845062689, 117376545230379631, 3149059523347103293, 84522568856319875179, 2269506752111508954553
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Crossrefs

Cf. A097190.

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 20); Coefficients(R!( 3/((1-27*x) +2*(1-27*x)^(8/9)) )); // G. C. Greubel, Sep 17 2019
    
  • Maple
    seq(coeff(series(3/((1-27*x) +2*(1-27*x)^(8/9)), x, n+1), x, n), n = 0 ..20); # G. C. Greubel, Sep 17 2019
  • Mathematica
    CoefficientList[Series[3/((1-27*x) +2*(1-27*x)^(8/9)), {x,0,20}], x] (* G. C. Greubel, Sep 17 2019 *)
  • PARI
    a(n)=polcoeff(3/((1-27*x) + 2*(1-27*x+x*O(x^n))^(8/9)),n,x)
    
  • Sage
    def A097194_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P(3/((1-27*x) +2*(1-27*x)^(8/9))).list()
    A097194_list(20) # G. C. Greubel, Sep 17 2019

Formula

G.f.: A(x) = 3/((1-27*x) + 2*(1-27*x)^(8/9)).
G.f.: A(x, y) = A097192(x)/(1 - x*A097193(x)).

A097186 Triangle read by rows in which row n gives coefficients of polynomial R_n(y) that satisfies R_n(1/3) = 3^n, where R_n(y) forms the initial (n+1) terms of g.f. A057083(y)^(n+1).

Original entry on oeis.org

1, 1, 6, 1, 9, 45, 1, 12, 78, 360, 1, 15, 120, 675, 2970, 1, 18, 171, 1134, 5859, 24948, 1, 21, 231, 1764, 10458, 51030, 212058, 1, 24, 300, 2592, 17334, 95256, 445824, 1817640, 1, 27, 378, 3645, 27135, 165726, 861597, 3905253, 15677145, 1, 30, 465, 4950, 40590, 272646, 1557765, 7760610, 34285680, 135868590
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Comments

Row sums form A097189. Main diagonal is A004988. Ratio of g.f.s of any two adjacent diagonals equals g.f. of A097188, where the g.f.s satisfy: A057083(x*A097188(x)) = A097188(x).

Examples

			Row polynomials evaluated at y=1/3 equals powers of 3:
3^1 = 1 + 6/3;
3^2 = 1 + 9/3 + 45/3^2;
3^3 = 1 + 12/3 + 78/3^2 + 360/3^3;
3^4 = 1 + 15/3 + 120/3^2 + 675/3^3 + 2970/3^4;
where A057083(y)^(n+1) has the same initial terms as the n-th row:
A057083(y) = 1 + 3y + 6y^2 + 9y^3 + 9y^4 + 0y^5 - 27y^6 +...
A057083(y)^2 = 1 + 6y +...
A057083(y)^3 = 1 + 9y + 45y^2 +...
A057083(y)^4 = 1 + 12y + 78y^2 + 360y^3 +...
A057083(y)^5 = 1 + 15y + 120y^2 + 675y^3 + 2970y^4 +...
Rows begin with n=0:
  1;
  1,  6;
  1,  9,  45;
  1, 12,  78,  360;
  1, 15, 120,  675,  2970;
  1, 18, 171, 1134,  5859,  24948;
  1, 21, 231, 1764, 10458,  51030, 212058;
  1, 24, 300, 2592, 17334,  95256, 445824, 1817640;
  1, 27, 378, 3645, 27135, 165726, 861597, 3905253, 15677145; ...
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[3y/((1-9xy) - (1-3y)*(1-9xy)^(2/3)), {x,0,n}, {y,0,k}], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 17 2019 *)
  • PARI
    {T(n,k)=if(n==0,1,if(k==0,1,if(k==n, 3^n*(3^n -sum(j=0,n-1, T(n,j)/3^j)), polcoeff((Ser(vector(n,i,T(n-1,i-1)), x) +x*O(x^k))^((n+1)/n),k,x))))}

Formula

G.f.: A(x, y) = 3*y/((1-9*x*y) + (3*y-1)*(1-9*x*y)^(2/3)).
G.f.: A(x, y) = A004988(x*y)/(1 - x*A097188(x*y)).

Extensions

More terms added by G. C. Greubel, Sep 17 2019
Showing 1-5 of 5 results.