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 1-8 of 8 results.

A194084 Triangle read by rows: a(n)=A135929(n) + A192011(n). Row n gives coefficients of polynomials BC(n,x) in order of decreasing exponents.

Original entry on oeis.org

0, 3, 0, 3, 0, 3, 3, 0, 0, 0, 3, 0, -3, 0, -3, 3, 0, -6, 0, -3, 0, 3, 0, -9, 0, 0, 0, 3, 3, 0, -12, 0, 6, 0, 6, 0, 3, 0, -15, 0, 15, 0, 6, 0, -3, 3, 0, -18, 0, 27, 0, 0, 0, -9, 0
Offset: 0

Views

Author

Paul Curtz, Aug 14 2011

Keywords

Comments

0,
3, 0,
3, 0, 3,
3, 0, 0, 0,
3, 0, -3, 0, -3,
3, 0, -6, 0, -3, 0.
Multiples of 3.
Row sum (from the second) is period 6: 3*A057079(n),"from" A057083 (scaled Chebyshev U(n,x)).
If a(0)=-3, a(n)=3*A192174(n).

Examples

			a(0)=1-1=0, a(1)=1+2=3, a(2)=0+0=0.
		

Formula

BC(0,x)=0, BC(1,x)=3*x, BC(2,x)=3*x^2+3, BC(n,x)=x*BC(n-1,x) - BC(n-2,x), n > 2.

A198862 Sum of the n-th antidiagonal in the triangle A192011.

Original entry on oeis.org

-1, 2, 2, 2, 3, 1, -1, -3, -6, -7, -6, -3, 3, 10, 16, 19, 16, 6, -10, -29, -45, -51, -41, -12, 33, 84, 125, 137, 104, 20, -105, -242, -346, -366, -261, -19, 327, 693, 954, 973, 646, -47, -1001, -1974, -2620, -2573, -1572, 402, 3022
Offset: 0

Views

Author

Paul Curtz, Oct 30 2011

Keywords

Comments

The current sequence and its successive differences are:
-1, 2, 2, 2, 3, 1, -1 ,-3, -6, -7, ...
3, 0, 0, 1, -2, -2, -2, -3, -1, 1, 3, 6, 7, 6, 3, -3, -10, -16, ...
-3, 0, 1, -3, 0, 0, -1, 2, 2, 2, 3, 1, -1, -3, -6, -7, -6, ...
3, 1, -4, 3, 0, -1, 3, 0, 0, 1, -2, -2, -2, -3, -1, 1, 3, 6, 7, ...
-2, -5, 7, -3, -1, 4, -3, 0, 1, -3, 0, 0, -1, 2, 2, 2, 3, 1, ...
-3, 12, -10, 2, 5, -7, 3, 1, -4, 3, 0, -1, 3, 0, 0, 1, -2, ...
15, -22, 12, 3, -12, 10, -2, -5, 7, -3, -1, 4, -3, 0, ...
-37, 34, -9, -15, 22, -12, -3, 12, -10, 2, 5, -7, 3, 1, -4, ...
Each row obeys the same linear recurrence and is a version of the row 4 lines farther up in the same array shifted right by 12 places.

Programs

Formula

a(n) = Sum_{k=0..floor(n/2)} A192011(n-k,k).
a(n) = a(n-1) - a(n-4), n > 3.
From R. J. Mathar, Nov 02 2011: (Start)
G.f.: (-1 + 3*x) / (1 - x + x^4).
a(n) = 3*A099530(n-1) - A099530(n). (End)

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

A053119 Triangle of coefficients of Chebyshev's S(n,x) polynomials (exponents in decreasing order).

Original entry on oeis.org

1, 1, 0, 1, 0, -1, 1, 0, -2, 0, 1, 0, -3, 0, 1, 1, 0, -4, 0, 3, 0, 1, 0, -5, 0, 6, 0, -1, 1, 0, -6, 0, 10, 0, -4, 0, 1, 0, -7, 0, 15, 0, -10, 0, 1, 1, 0, -8, 0, 21, 0, -20, 0, 5, 0, 1, 0, -9, 0, 28, 0, -35, 0, 15, 0, -1, 1, 0, -10, 0, 36, 0, -56, 0, 35, 0, -6, 0, 1, 0, -11, 0, 45, 0, -84, 0, 70, 0, -21, 0, 1
Offset: 0

Views

Author

Keywords

Comments

These polynomials also give the determinant of the tridiagonal matrix having x on the diagonal and -1 next to these x. - M. F. Hasler, Oct 15 2019
The polynomial S(n,x) is the character of the irreducible (n+1) dimensional representation of the Lie algebra sl_2 when x is the character of irreducible 2-dimesional representation. - Leonid Bedratyuk, Oct 28 2023

Examples

			The triangle begins:
n\m 0  1   2  3   4  5   6  7   8  9  10 ...
0:  1
1:  1  0
2:  1  0  -1
3:  1  0  -2  0
4:  1  0  -3  0   1
5:  1  0  -4  0   3  0
6:  1  0  -5  0   6  0  -1
7:  1  0  -6  0  10  0  -4  0
8:  1  0  -7  0  15  0 -10  0   1
9:  1  0  -8  0  21  0 -20  0   5  0
10: 1  0  -9  0  28  0 -35  0  15  0  -1
... Reformatted. - _Wolfdieter Lang_, Dec 17 2013
E.g., fourth row (n=3) corresponds to polynomial S(3,x)= x^3-2*x.
Triangle of absolute values of coefficients (coefficients of Fibonacci polynomials) with exponents in increasing order begins:
[1]
[0, 1]
[1, 0, 1]
[0, 2, 0, 1]
[1, 0, 3, 0, 1]
[0, 3, 0, 4, 0, 1]
[1, 0, 6, 0, 5, 0, 1]
[0, 4, 0, 10, 0, 6, 0, 1]
[1, 0, 10, 0, 15, 0, 7, 0, 1]
[0, 5, 0, 20, 0, 21, 0, 8, 0, 1]
See A162515 for the Fibonacci polynomials with reversed row entries, starting there with row 1. - _Wolfdieter Lang_, Dec 16 2013
		

References

  • D. S. Mitrinovic, Analytic Inequalities, Springer-Verlag, 1970; p. 232, Sect. 3.3.38.
  • Theodore J. Rivlin, Chebyshev polynomials: from approximation theory to algebra and number theory, 2. ed., Wiley, New York, 1990.

Crossrefs

Row sums give A000045. Reflection of A049310.
Cf. A162515. - Wolfdieter Lang, Dec 16 2013

Programs

  • Maple
    A053119 := (n, k) -> if k::even then (-1)^binomial(k, 2)*binomial(n - k/2, k/2)
    else 0 fi: seq(seq(A053119(n, k), k = 0..n), n = 0..11); # Peter Luschny, Jul 20 2024
  • Mathematica
    ChebyshevS[n_, x_] := ChebyshevU[n, x/2]; Flatten[ Table[ Reverse[ CoefficientList[ ChebyshevS[n, x], x]], {n, 0, 12}]] (* Jean-François Alcover, Nov 25 2011 *)
  • PARI
    tabl(nn) = for (n=0, nn, print(Vec(polchebyshev(n, 2, x/2)))); \\ Michel Marcus, Jan 14 2016

Formula

a(n,m) = A049310(n,n-m).
G.f. for row polynomials S(n,x) (signed triangle): 1/(1-x*z+z^2).
Unsigned triangle |a(n,m)| has Fibonacci polynomials F(n+1,x) as row polynomials with G.f. 1/(1-x*z-z^2).
a(n, m) := 0 if n < m or m odd, else ((-1)^(3*m/2))*binomial(n-m/2, n-m); a(n, m) = a(n-1, m) - a(n-2, m-2), a(n, -2) := 0 =: a(n, -1), a(0, 0) = 1, a(n, m) = 0 if n < m or m odd.
G.f. for m-th column (signed triangle): (-1)^(3*m/2)*x^m/(1-x)^(m/2+1) if m >= 0 is even else 0.
Recurrence for the (unsigned) Fibonacci polynomials: F[1]=1, F[2]=x; for n>2, F[n] = x*F[n-1]+F[n-2].
a = 2*A192011 - 3*A192174. - Thomas Baruchel, Jun 02 2018
Recurrence for the polynomials S(n) = x S(n-1) - S(n-2); S(0) = 1, S(1) = x. - M. F. Hasler, Oct 15 2019

A219795 Sum of the absolute values of the antidiagonals of the triangle A135929(n) companion. See the comment.

Original entry on oeis.org

2, 2, 2, 2, 3, 3, 5, 7, 10, 11, 16, 23, 33, 44, 58, 81, 114, 158, 212, 293, 407, 565, 777, 1064, 1471, 2036, 2813, 3863, 5334, 7370, 10183, 14046, 19356, 26726, 36909, 50955, 70251, 96977, 133886, 184841, 255092
Offset: 0

Views

Author

Paul Curtz, Nov 28 2012

Keywords

Comments

The companion to A135929(n) is the triangle
2;
2, 0;
2, 0, 1;
2, 0, -1, 0;
2, 0, -3, 0, -1;
2, 0, -5, 0, 0, 0;
2, 0, -7, 0, 3, 0, 1;
2, 0, -9, 0, 8, 0, 1, 0;
(A192011(n) beginning with 2 instead of -1).
Consider a(1),a(5),a(10),a(14), that is, a(A193910(n) -1).
a(1)+a(4)-a(5) = 2, a(5)+a(8)-a(9) = 2, a(10)+a(13)-a(14) = 2, a(14)+a(17)-a(18) = 4, a(19)+a(22)-a(23) = 6, a(23)+a(26)-a(27) = 14, yields 2,2,2,4,6,14,24,60,... = 2*A047749(n) or 2, followed with A116637(n+1).

Examples

			a(0)=2, a(1)=2, a(2)=2+0, a(3)=2+0, a(4)=2+0+1, a(5)=2+0+1.
		

Programs

  • Maple
    A219795 := proc(n)
        if n=0 then
            2;
        else
            add(abs(A192011(n-k,k)),k=0..floor(n/2)) ;
        end if;
    end proc: # R. J. Mathar, Jan 06 2013

Formula

a(n) = sum abs ( [k=0..floor(n/2)] A192011(n-k,k) ), a(0)=2.

Extensions

a(24)-a(40) from Jean-Francois Alcover, Nov 28 2012

A174559 Triangle T(n,k)of the coefficients [x^(n-k)] of the polynomials q(0,x)=-1, q(1,x)=3*x, q(n,x)=x*q(n-1,x)-q(n-2,x) in row n,column k. A companion to A193002(n).

Original entry on oeis.org

-1, 3, 0, 3, 0, 1, 3, 0, -2, 0, 3, 0, -5, 0, -1, 3, 0, -8, 0, 1, 0, 3, 0, -11, 0, 6, 0, 1, 3, 0, -14, 0, 14, 0, 0, 0, 3, 0, -17, 0, 25, 0, -6, 0, -1, 3, 0, -20, 0, 39, 0, -20, 0, -1, 0, 3, 0, -23, 0, 56, 0, -45, 0, 5, 0, 1
Offset: 0

Views

Author

Paul Curtz, Aug 20 2011

Keywords

Comments

a(n)=
-1, :-1,
3, 0, :3*x,
3, 0, 1, :3*x^2+1,
3, 0, -2, 0, :3*x^3-2*x,
3, 0, -5, 0, -1,
3, 0, -8, 0, 1, 0
3, 0, -11, 0, 6, 0, 1.
Row sum=period 6:repeat -1, 3, 4, 1, -3, 4=-A117378(n)=A117378(n+3).

Crossrefs

Cf. A192011.

Formula

a(n) + A193002(n)=4*A192174(n).
a(n) - A193002(n)=2*A053119(n), Chebyshev's S(n,x).

A195662 Triangle T(n,k) read by rows: T(0,0)= -3, T(1,0)= 2, T(1,1) = 0 and T(n,k) = T(n-1,k) -T(n-2,k-2) otherwise.

Original entry on oeis.org

-3, 2, 0, 2, 0, 3, 2, 0, 1, 0, 2, 0, -1, 0, -3, 2, 0, -3, 0, -4, 0, 2, 0, -5, 0, -3, 0, 3, 2, 0, -7, 0, 0, 0, 7, 0, 2, 0, -9, 0, 5, 0, 10, 0, -3, 2, 0, -11, 0, 12, 0, 10, 0, -10, 0, 2, 0, -13, 0, 21, 0, 5, 0, -20, 0, 3, 2, 0, -15, 0, 32, 0, -7, 0, -30, 0, 13, 0
Offset: 0

Views

Author

Paul Curtz, Sep 22 2011

Keywords

Comments

In the notation of A195673, this defines polynomials P(n,x,p=-3,q=2), where p and q are the values of the constant and linear order for n=0 and 1.
Row sums -- the value P(n,1,-3,2) of the polynomial -- are A130848(n+5).
For general seed values in the two top rows of the triangle, the recurrence T(n,k) = T(n-1,k) - T(n-2,k-2) defines the triangle
p;
q, 0;
q, 0, -p;
q, 0, -p-q, 0;
q, 0, -p-2q, 0, p;
q, 0, -p-3q, 0, 2p+q, 0;
and a companion triangle by adding 1 to both seed values:
p+1;
q+1, 0;
q+1, 0, -p-1;
q+1, 0, -p-q-2, 0;
q+1, 0, -p-2q-3, 0, p+1;
q+1, 0, -p-3q-4, 0, 2p+q+3, 0;
The point-by-point difference between two companions is P(n,x,p+1,q+1) - P(n,x,p,q) = S(n,x) as represented (with increasing exponents) by A053119.
Examples of such triangles are A053119 (p=q=1), A192575 (p=1, q=2),
A162514 (p=2, q=1, up to a sign factor), A192011 (p=-1, q=2), A135929 (p=-2, q=1, apart from a irregular leading T(0,0)).

Examples

			The first few rows are
-3;
2, 0;
2, 0,   3;
2, 0,   1, 0;
2, 0,  -1, 0, -3;
2, 0,  -3, 0, -4, 0;
2, 0,  -5, 0, -3, 0,  3;
2, 0,  -7, 0,  0, 0,  7, 0;
2, 0,  -9, 0,  5, 0, 10, 0,  -3;
2, 0, -11, 0, 12, 0, 10, 0, -10, 0;
2, 0, -13, 0, 21, 0,  5, 0, -20, 0, 3;
		

Crossrefs

Programs

  • Mathematica
    p = -3; q = 2; t[0, 0] = p; t[, 0] = 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, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Nov 27 2012 *)

Formula

T(n,0) = 2 (n>0).
T(n,2) = -A060747(n-3), n>2.
T(n,4) = A028347(n-5), n>6.
T(2n,2n) = -3*(-1)^n ; T(n, 2k-1) = 0 ; T(2n+1,2n) = -(3n-2)*(-1)^n. - M. F. Hasler, Sep 28 2011

A195673 Triangle T(n,k) read by rows: T(0,0)=-2, T(1,0)=3, T(1,1)=0 and T(n,k) = T(n-1,k)-T(n-2,k-2) otherwise.

Original entry on oeis.org

-2, 3, 0, 3, 0, 2, 3, 0, -1, 0, 3, 0, -4, 0, -2, 3, 0, -7, 0, -1, 0, 3, 0, -10, 0, 3, 0, 2, 3, 0, -13, 0, 10, 0, 3, 0, 3, 0, -16, 0, 20, 0, 0, 0, -2, 3, 0, -19, 0, 33, 0, -10, 0, -5, 0, 3, 0, -22, 0, 49, 0, -30, 0, -5, 0, 2, 3, 0, -25, 0, 68
Offset: 0

Views

Author

Paul Curtz, Sep 23 2011

Keywords

Comments

Obviously T(n,k) = 0 for all odd k.
Conjecture: The polynomials p(n,x) = sum_{k=0..n} T(n,k)*x^(n-k) based on this simple recurrence for other initial constant values of T(0,0)=p and T(1,0)=q are related to the S-polynomials of A053119: p(n,x,p+1,q+1)-p(n,x,p,q) = S(n,x).

Examples

			-2;
3, 0;
3, 0,   2;
3, 0,  -1, 0;
3, 0,  -4, 0, -2;
3, 0,  -7, 0, -1, 0;
3, 0, -10, 0,  3, 0, 2;
3, 0, -13, 0, 10, 0, 3, 0.
		

Crossrefs

Cf. A195662, A192011 (p=-1, q=2), A135929 (p=-2, q=1).
Showing 1-8 of 8 results.