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 13 results. Next

A136255 Triangle T(n,k) read by rows: T(n,k) = (k+1) * A137276(n,k+1).

Original entry on oeis.org

1, 0, 2, 1, 0, 3, 0, 0, 0, 4, -3, 0, -3, 0, 5, 0, -6, 0, -8, 0, 6, 5, 0, -6, 0, -15, 0, 7, 0, 16, 0, 0, 0, -24, 0, 8, -7, 0, 30, 0, 15, 0, -35, 0, 9, 0, -30, 0, 40, 0, 42, 0, -48, 0, 10, 9, 0, -75, 0, 35, 0, 84, 0, -63, 0, 11
Offset: 1

Views

Author

Roger L. Bagula, Mar 17 2008

Keywords

Comments

Row sums are 1, 2, 4, 4, -1, -8, -9, 0, 12, 14, 1, ... with g.f. x*(1+3*x^2) / (x^2-x+1)^2.

Examples

			Triangle starts:
{1},
{0, 2},
{1, 0, 3},
{0, 0, 0, 4},
{-3, 0, -3, 0, 5},
{0, -6, 0, -8, 0, 6},
{5, 0, -6, 0, -15, 0, 7},
{0, 16, 0, 0, 0, -24, 0, 8},
{-7, 0, 30, 0, 15, 0, -35, 0, 9},
{0, -30, 0, 40, 0,42, 0, -48, 0, 10},
{9, 0, -75, 0, 35, 0, 84, 0, -63, 0, 11},
...
		

Crossrefs

Programs

  • Maple
    B := proc(n,x) if n = 0 then 1; else add( (-1)^j*binomial(n-j,j)*(n-4*j)/(n-j)*x^(n-2*j),j=0..n/2) ; fi; end:
    A136255 := proc(n,k) diff( B(n,x),x) ; coeftayl(%,x=0,k) ; end: seq( seq(A136255(n,k),k=0..n-1),n=1..15) ;
  • Mathematica
    B[x, 0] = 1; B[x, 1] = x; B[x, 2] = 2 + x^2; B[x, 3] = x + x^3; B[x, 4] = -2 + x^4; B[x_, n_] := B[x, n] = x*B[x, n-1] - B[x, n-2]; P[x_, n_] := D[B[x, n + 1], x]; Flatten @ Table[CoefficientList[P[x, n], x], {n, 0, 10}]

Formula

T(n,k) = (k+1) * A137276(n,k+1) .

Extensions

Edited by the Associate Editors of the OEIS, Aug 27 2009
Edited by and new name from Joerg Arndt, May 15 2016

A136256 Triangle of the coefficients [x^k] of the linear form (x*B_{n-1}(x)-(d/dx) B_n(x)) of the polynomials defined in A137276, 0<=k<=n.

Original entry on oeis.org

0, -1, 1, 0, -2, 1, -1, 2, -3, 1, 0, 0, 1, -4, 1, 3, -2, 3, 0, -5, 1, 0, 6, -3, 8, -1, -6, 1, -5, 2, 6, -3, 15, -2, -7, 1, 0, -16, 5, 0, -2, 24, -3, -8, 1, 7, -2, -30, 8, -15, 0, 35, -4, -9, 1, 0, 30, -7, -40, 10, -42, 3, 48, -5, -10, 1, -9, 2, 75, -15, -35, 10, -84, 7, 63, -6, -11, 1
Offset: 0

Views

Author

Roger L. Bagula, Mar 18 2008

Keywords

Comments

Row sums are: 0, 0, -1, -1, -2, 0, 5, 7, 1, -9, -12, -2, 13, 17, 3, -17, -22, -4, 21, 27, 5

Examples

			0;
-1, 1;
0, -2, 1;
-1, 2, -3, 1;
0, 0, 1, -4, 1;
3, -2, 3, 0, -5, 1;
0, 6, -3, 8, -1, -6, 1;
-5, 2, 6, -3, 15, -2, -7, 1;
0, -16, 5, 0, -2, 24, -3, -8, 1;
7, -2, -30, 8, -15, 0, 35, -4, -9, 1;
0, 30, -7, -40, 10, -42, 3, 48, -5, -10, 1;
-9, 2, 75, -15, -35, 10, -84, 7, 63, -6, -11, 1;
		

References

  • Harry Hochstadt, Defined differential recursion, The Functions of Mathematical Physics, Dover (New York) (1986), page 49.

Crossrefs

Cf. A138034.

Programs

  • Maple
    B := proc(n,x) option remember; if n < 0 then 0; elif n = 0 then 1; elif n = 1 then x; elif n = 2 then x^2+2 else x*procname(n-1,x)-procname(n-2,x) ; expand(%) ; end if; end proc:
    BB := proc(n,x) x*B(n-1,x)-diff(B(n,x),x) ; expand(%) ; end proc:
    A136256 := proc(n,k) coeftayl(BB(n,x),x=0,k) ; end proc:
    seq(seq(A136256(n,k),k=0..n),n=0..10) ; # R. J. Mathar, Sep 04 2011

Formula

T(n,k) = A137276(n-1,k-1) - k*A137276(n,k+1). - R. J. Mathar, Sep 05 2011

A135929 Triangle read by rows: row n gives coefficients of polynomial P_n(x)= U_{n}(x,1) + 3 * U_{n-2}(x,1) where U is the Chebyshev polynomial of the second kind, in order of decreasing exponents.

Original entry on oeis.org

1, 1, 0, 1, 0, 2, 1, 0, 1, 0, 1, 0, 0, 0, -2, 1, 0, -1, 0, -3, 0, 1, 0, -2, 0, -3, 0, 2, 1, 0, -3, 0, -2, 0, 5, 0, 1, 0, -4, 0, 0, 0, 8, 0, -2, 1, 0, -5, 0, 3, 0, 10, 0, -7, 0, 1, 0, -6, 0, 7, 0, 10, 0, -15, 0, 2, 1, 0, -7, 0, 12, 0, 7, 0, -25, 0, 9, 0, 1, 0, -8, 0, 18, 0, 0, 0, -35, 0, 24, 0, -2
Offset: 0

Views

Author

N. J. A. Sloane, Mar 09 2008

Keywords

Comments

Take a(0)=-2 instead of 1. The recurrence begins immediately (at the third instead of the fourth polynomial). Companion: A192011(n). - Paul Curtz, Sep 20 2011

Examples

			The coefficients and polynomials are
  1;                                 1
  1, 0;                              x
  1, 0,  2;                          x^2 + 2
  1, 0,  1, 0;                       x^3 +   x
  1, 0,  0, 0, -2;                   x^4 - 2
  1, 0, -1, 0, -3, 0;                x^5 -   x^3 - 3*x
  1, 0, -2, 0, -3, 0,  2;            x^6 - 2*x^4 - 3*x^2 + 2
  1, 0, -3, 0, -2, 0,  5, 0;         x^7 - 3*x^5 - 2*x^3 + 5*x
  1, 0, -4, 0,  0, 0,  8, 0, -2;     x^8 - 4*x^6 + 8*x^2 - 2
  1, 0, -5, 0,  3, 0, 10, 0, -7, 0;  x^9 - 5*x^7 + 3*x^5 + 10*x^3 - 7*x
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972; see Chapter 22.

Crossrefs

Programs

  • Magma
    A053119:= func< n,k | (1/2)*(-1)^Floor(3*k/2)*(1+(-1)^k)*Binomial(n - Floor(k/2), n-k) >;
    A135929:= func< n,k | n eq 0 select 1 else A053119(n, k) + 3*A053119(n-2, k-2) >;
    [A135929(n,k): k in [0..n], n in [0..16]]; // G. C. Greubel, Apr 24 2023
    
  • Maple
    A135929 := proc(n, m) coeftayl( coeftayl( (1+3*t^2)/(1-x*t+t^2), t=0, n), x=0, n-m) ; end proc: seq(seq(A135929(n,m), m=0..n),n=0..14) ; # R. J. Mathar, Nov 03 2009
  • Mathematica
    p[0, ]= 1; p[1, x]:= x; p[2, x_]:= x^2+2; p[n_, x_]:= p[n, x] = x*p[n-1, x] - p[n-2, x]; row[n_]:= CoefficientList[p[n, x], x]; Table[row[n]//Reverse, {n, 0, 13}]//Flatten (* Jean-François Alcover, Nov 26 2012, after Paul Curtz's formula *)
    (* Second program *)
    p=1; q=2; t[, 0]=p; t[2, 2]=q; t[, ?OddQ]=0; t[n, k_] /; k > n = 0; t[n_ /; n >= 0, k_ /; k >= 0]:= t[n, k] = t[n-1, k] - t[n-2, k-2]; Table[t[n, k], {n, 0, 13}, {k, 0, n}]//Flatten (* Jean-François Alcover, Nov 27 2012, from recurrence *)
  • SageMath
    def A053119(n,k): return (-1)^(3*k/2)*((k+1)%2)*binomial(n-k/2, n-k)
    def A135929(n,k): return 1 if (n==0) else A053119(n, k) + 3*A053119(n-2, k-2)
    flatten([[A135929(n,k) for k in range(n+1)] for n in range(16)]) # G. C. Greubel, Apr 24 2023

Formula

G.f.: (1+3*t^2)/(1-x*t+t^2).
P_n(x) = U_{n}(x,1) + 3 * U_{n-2}(x,1) for n>=2. - Max Alekseyev, Dec 04 2009
P_n(x) = S_{n}(x) + 3*S_{n-2}(x), with Chebyshev Polynomials S_n(x) defined in A049310 and A053119. - R. J. Mathar, Dec 07 2009
P_0(x)=1, P_1(x)=x, P_2(x)=x^2+2, and P_n(x)= x*P_{n-1}(x) - P_{n-2}(x) for n>=3. - Paul Curtz, Aug 14 2011
From G. C. Greubel, Apr 24 2023: (Start)
T(n, k) = A053119(n, k) + 3*A053119(n-2, k-2), with T(0,0) = 1.
Sum_{k=0..n} T(n, k) = A138034(n). (End)

Extensions

Extended by R. J. Mathar, Nov 03 2009

A138034 Expansion of (1+3*x^2)/(1-x+x^2).

Original entry on oeis.org

1, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3
Offset: 0

Views

Author

Karem Boubaker (mmbb11112000(AT)yahoo.fr), Mar 01 2008; corrected Mar 03 2008

Keywords

Comments

Essentially a duplicate of A119910: 1, followed by A119910. - Joerg Arndt, Nov 14 2014

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(1 + 3*x^2)/(1 - x + x^2), {x, 0, 100}], x] (* Wesley Ivan Hurt, Jan 15 2017 *)
    LinearRecurrence[{1,-1},{1,1,3},120] (* Harvey P. Dale, Jun 14 2024 *)

Formula

a(n) = A119910(n), n>=1.
G.f.: (1+3*x^2)/(1-x+x^2). a(n)=a(n-1)-a(n-2), n>2.

A167541 a(n) = -(n - 4)*(n - 5)*(n - 12)/6.

Original entry on oeis.org

2, 5, 8, 10, 10, 7, 0, -12, -30, -55, -88, -130, -182, -245, -320, -408, -510, -627, -760, -910, -1078, -1265, -1472, -1700, -1950, -2223, -2520, -2842, -3190, -3565, -3968, -4400, -4862, -5355, -5880, -6438, -7030, -7657, -8320, -9020, -9758, -10535, -11352
Offset: 6

Views

Author

Jamel Ghanouchi, Nov 06 2009

Keywords

Comments

Essentially the same as A111396.
The coefficient of x^(n-6) of the Polynomial B_n(x) defined in A135929.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{4,-6,4,-1},{2,5,8,10},50] (* Harvey P. Dale, May 27 2012 *)

Formula

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
G.f.: x^6*(2 - 3*x)/(x - 1)^4.
a(n) = -A111396(n-12) for n > 11. - Bruno Berselli, Oct 02 2018

Extensions

Minor edits by N. J. A. Sloane, Nov 09 2009
Definition simplified, sequence extended by R. J. Mathar, Nov 12 2009

A167373 Expansion of (1+x)*(3*x+1)/(1+x+x^2).

Original entry on oeis.org

1, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1, -2, 3, -1
Offset: 0

Views

Author

Jamel Ghanouchi, Nov 02 2009

Keywords

Comments

Bisection of A138034.
Also row 2n of A137276 or A135929.

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972, Chapter 22.

Crossrefs

Programs

  • Maple
    A167373 := proc(n)
        option remember;
        if n < 4 then
            op(n+1,[1,3,-1,-2]) ;
        else
            procname(n-3) ;
        end if;
    end proc:
    seq(A167373(n),n=0..20) ; # R. J. Mathar, Feb 06 2020
  • Mathematica
    CoefficientList[Series[(1 + x)*(3*x + 1)/(1 + x + x^2), {x, 0, 50}], x] (* G. C. Greubel, Jun 12 2016 *)
    LinearRecurrence[{-1,-1},{1,3,-1},120] (* Harvey P. Dale, Apr 05 2023 *)

Formula

G.f.: (1+x)*(3*x+1)/(1+x+x^2).
a(n) = a(n-3), n>4.
a(n) = - a(n-1) - a(n-2) for n>2.
a(n) = 4*sin(2*n*Pi/3)/sqrt(3)-2*cos(2*n*Pi/3) for n>0 with a(0)=1. - Wesley Ivan Hurt, Jun 12 2016

Extensions

Edited by R. J. Mathar, Nov 03 2009
Further edited and extended by Simon Plouffe, Nov 23 2009
Recomputed by N. J. A. Sloane, Dec 20 2009

A167544 a(n) = (n-3)*(n-8)/2.

Original entry on oeis.org

-2, -3, -3, -2, 0, 3, 7, 12, 18, 25, 33, 42, 52, 63, 75, 88, 102, 117, 133, 150, 168, 187, 207, 228, 250, 273, 297, 322, 348, 375, 403, 432, 462, 493, 525, 558, 592, 627, 663, 700, 738, 777, 817, 858, 900, 943, 987, 1032, 1078, 1125, 1173
Offset: 4

Views

Author

Jamel Ghanouchi, Nov 06 2009

Keywords

Comments

Essentially a duplicate of A055998.

Crossrefs

Programs

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
G.f.: x^4*(-2 + 3*x)/(1-x)^3.
a(n) = A055998(n-8). - Philippe Deléham, Nov 25 2009
a(n) = a(n-1) + n - 6 (with a(4)=-2). - Vincenzo Librandi, Dec 05 2010
a(n) = A027379(n-8) for n >= 9. - Georg Fischer, Oct 24 2018
E.g.f.: (1/2)*( (24 -10*x + x^2)*exp(x) - (24 + 14*x + 3*x^2) ). - G. C. Greubel, Jul 30 2022

Extensions

Edited and extended by R. J. Mathar, Nov 12 2009

A137277 Triangle of the coefficients [x^k] P_n(x) of the polynomials P_n(x) = 1/n * sum(j=0..floor(n/2), (-1)^j * binomial(n,j) * (n-4*j) * x^(n-2*j) ).

Original entry on oeis.org

1, 0, 1, 2, 0, 1, 0, 1, 0, 1, -6, 0, 0, 0, 1, 0, -6, 0, -1, 0, 1, 20, 0, -5, 0, -2, 0, 1, 0, 25, 0, -3, 0, -3, 0, 1, -70, 0, 28, 0, 0, 0, -4, 0, 1, 0, -98, 0, 28, 0, 4, 0, -5, 0, 1, 252, 0, -126, 0, 24, 0, 9, 0, -6, 0, 1, 0, 378, 0, -150, 0, 15, 0, 15, 0, -7, 0, 1, -924, 0, 528, 0, -165, 0, 0, 0, 22, 0, -8, 0, 1, 0, -1452
Offset: 0

Views

Author

Roger L. Bagula, Mar 13 2008

Keywords

Comments

The first four P_n(x) are the same as in A137276.
Row sums are 1, 1, 3, 2, -5, -6, 14, 20, -45, -70, 154, a signed variant of A047074.

Examples

			{1}, = 1
{0, 1}, = x
{2, 0, 1}, = 2+x^2
{0, 1, 0, 1}, = x+x^3
{-6, 0, 0, 0, 1}, = -6+x^4
{0, -6, 0, -1, 0, 1},
{20, 0, -5, 0, -2, 0, 1},
{0, 25, 0, -3,0, -3, 0, 1},
{-70, 0, 28, 0, 0, 0, -4, 0, 1},
{0, -98, 0, 28, 0,4, 0, -5, 0, 1},
{252, 0, -126, 0, 24, 0, 9, 0, -6, 0, 1}
		

Crossrefs

Cf. A138034.

Programs

  • Maple
    A137277 := proc(n,k) if n = 0 then 1; else add( (-1)^j*binomial(n,j)*(n-4*j)*x^(n-2*j),j=0..n/2)/n ; coeftayl(%,x=0,k) ; fi; end:
    seq( seq(A137277(n,k),k=0..n),n=0..15) ;
  • Mathematica
    B[x_, n_] = If[n > 0, Sum[(-1)^p*Binomial[n,p]*(n - 4*p)*x^(n - 2*p)/ n, {p, 0, Floor[n/2]}], 1]; a = Table[CoefficientList[B[x, n], x], {n, 0, 10}]; Flatten[a]

Formula

P(0,n)=1. P_n(x) = 1/n*sum(j=0..floor(n/2), (-1)^j*binomial(n,j)*(n-4*j)*x^(n-2*j)).

Extensions

Edited by the Associate Editors of the OEIS, Aug 27 2009

A161718 Expansion of (1+3*x^2)/(1+x)^2.

Original entry on oeis.org

1, -2, 6, -10, 14, -18, 22, -26, 30, -34, 38, -42, 46, -50, 54, -58, 62, -66, 70, -74, 78, -82, 86, -90, 94, -98, 102, -106, 110, -114, 118, -122, 126, -130, 134, -138, 142, -146, 150, -154, 158, -162, 166, -170, 174, -178, 182, -186, 190, -194, 198, -202, 206, -210, 214, -218, 222, -226, 230, -234
Offset: 0

Views

Author

Pr Mosbah Amlouk (Mosbah.Amlouk(AT)fsb.rnu.tn), Jun 17 2009

Keywords

Crossrefs

Cf. A016825, A111284 (unsigned version), A135929, A137276.

Programs

  • Mathematica
    CoefficientList[Series[(1+3*x^2)/(1+x)^2,{x,0,80}],x] (* or *) LinearRecurrence[ {-2,-1},{1,-2,6},80] (* Harvey P. Dale, Mar 19 2016 *)
  • PARI
    x='x+O('x^99); Vec((1+3*x^2)/(1+x)^2) \\ Altug Alkan, Apr 17 2018

Formula

From R. J. Mathar, Aug 27 2009: (Start)
a(n) = -2*a(n-1)-a(n-2), n>3.
G.f.: (1+3*x^2)/(1+x)^2.
a(n) = 4*(-1)^n*n+2*(-1)^(n+1) = (-1)^n*A016825(n-1), n>0. (End)
E.g.f.: 3 - 2*exp(-x)*(1 + 2*x). - Stefano Spezia, Feb 02 2023

Extensions

Spurious commas in sequence deleted by N. J. A. Sloane, Aug 02 2009
Offset corrected, extended by R. J. Mathar, Aug 27 2009
Edited by Joerg Arndt, Sep 04 2011

A167387 a(n) = (-1)^(n+1) * n*(n-1)*(n-4)*(n+1)/12.

Original entry on oeis.org

1, -2, 0, 10, -35, 84, -168, 300, -495, 770, -1144, 1638, -2275, 3080, -4080, 5304, -6783, 8550, -10640, 13090, -15939, 19228, -23000, 27300, -32175, 37674, -43848, 50750, -58435, 66960, -76384, 86768, -98175, 110670, -124320, 139194, -155363, 172900
Offset: 2

Views

Author

Jamel Ghanouchi, Nov 02 2009

Keywords

Comments

The coefficient of [x^4] of the Polynomial B_{2n}(x) defined in A137276.
Essentially the same as A052472.

Crossrefs

Programs

  • GAP
    List([2..40], n-> (-1)^(n+1)*(n-4)*Binomial(n+1,3)/2); # G. C. Greubel, May 19 2019
  • Magma
    [(-1)^(n+1)*n*(n-1)*(n-4)*(n+1)/12: n in [2..40]]; // Vincenzo Librandi, Jun 13 2016
    
  • Mathematica
    Table[(-1)^(n+1)*(n+1)*n*(n-1)*(n-4)/12, {n, 2, 40}] (* G. C. Greubel, Jun 12 2016 *)
    LinearRecurrence[{-5, -10, -10, -5, -1}, {1, -2, 0, 10, -35}, 40] (* Vincenzo Librandi, Jun 13 2016 *)
  • PARI
    vector(40, n, n++; (-1)^(n+1)*(n-4)*binomial(n+1,3)/2) \\ G. C. Greubel, May 19 2019
    
  • Sage
    [(-1)^(n+1)*(n-4)*binomial(n+1,3)/2 for n in (2..40)] # G. C. Greubel, May 19 2019
    

Formula

a(n) = -5*a(n-1) -10*a(n-2) -10*a(n-3) -5*a(n-4) -a(n-5).
G.f.: x^2*(1+3*x)/(1+x)^5.
E.g.f.: x^2*(6 + 2*x - x^2)*exp(-x)/12. - G. C. Greubel, May 19 2019
Showing 1-10 of 13 results. Next