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 1-7 of 7 results.

A101950 Product of A049310 and A007318 as lower triangular matrices.

Original entry on oeis.org

1, 1, 1, 0, 2, 1, -1, 1, 3, 1, -1, -2, 3, 4, 1, 0, -4, -2, 6, 5, 1, 1, -2, -9, 0, 10, 6, 1, 1, 3, -9, -15, 5, 15, 7, 1, 0, 6, 3, -24, -20, 14, 21, 8, 1, -1, 3, 18, -6, -49, -21, 28, 28, 9, 1, -1, -4, 18, 36, -35, -84, -14, 48, 36, 10, 1, 0, -8, -4, 60, 50, -98, -126, 6, 75, 45, 11, 1, 1, -4, -30, 20, 145, 36, -210
Offset: 0

Views

Author

Paul Barry, Dec 22 2004

Keywords

Comments

A Chebyshev and Pascal product.
Row sums are n+1, diagonal sums the constant sequence 1 resp. A023434(n+1). Riordan array (1/(1-x+x^2),x/(1-x+x^2)).
Apart from signs, identical with A104562.
Subtriangle of the triangle given by [0,1,-1,1,0,0,0,0,0,0,0,...] DELTA [1,0,0,0,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Jan 27 2010
The Fi1 and Fi2 sums lead to A004525 and the Gi1 sums lead to A077889, see A180662 for the definitions of these triangle sums. - Johannes W. Meijer, Aug 06 2011
Also the convolution triangle of the inverse of 6th cyclotomic polynomial A010892. - Peter Luschny, Oct 08 2022

Examples

			Triangle begins:
   1,
   1, 1,
   0, 2, 1,
  -1, 1, 3, 1,
  -1,-2, 3, 4, 1,
  ...
Triangle [0,1,-1,1,0,0,0,0,...] DELTA [1,0,0,0,0,0,...] begins : 1 ; 0,1 ; 0,1,1 ; 0,0,2,1 ; 0,-1,1,3,1 ; 0,-1,-2,3,4,1 ; ... - _Philippe Deléham_, Jan 27 2010
		

Crossrefs

Programs

  • Maple
    A101950 := proc(n,k) local j,k1: add((-1)^((n-j)/2)*binomial((n+j)/2,j)*(1+(-1)^(n+j))* binomial(j,k)/2, j=0..n) end: seq(seq(A101950(n,k),k=0..n), n=0..11); # Johannes W. Meijer, Aug 06 2011
    # Uses function PMatrix from A357368. Adds a row on top and a column to the left.
    PMatrix(10, n -> [0, 1, 1, 0, -1,-1][irem(n, 6) + 1]); # Peter Luschny, Oct 08 2022
  • Mathematica
    T[0, 0] = 1; T[n_, k_] /; k>n || k<0 = 0; T[n_, k_] := T[n, k] = T[n-1, k-1]+T[n-1, k]-T[n-2, k]; Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Mar 07 2014, after Philippe Deléham *)

Formula

T(n, k) = Sum_{j=0..n} (-1)^((n-j)/2)*C((n+j)/2,j)*(1+(-1)^(n+j))*C(j,k)/2.
T(0,0) = 1, T(n,k) = 0,if k>n or if k<0, T(n,k) = T(n-1,k-1) + T(n-1,k) - T(n-2,k). - Philippe Deléham, Jan 26 2010
p(n,x) = (x+1)*p(n-1,x)-p(n-2,x) with p(0,x) = 1 and p(1,x) = x+1 [Dias].
G.f.: 1/(1-x-x^2-y*x). - Philippe Deléham, Feb 10 2012
T(n,0) = A010892(n), T(n+1,1) = A099254(n), T(n+2,2) = A128504(n). - Philippe Deléham, Mar 07 2014
T(n,k) = C(n,k)*hypergeom([(k-n)/2, (k-n+1)/2], [-n], 4) for n>=1. - Peter Luschny, Apr 25 2016

Extensions

Typo in formula corrected and information added by Johannes W. Meijer, Aug 06 2011

A128503 Array for second (k=2) convolution of Chebyshev's S(n,x)=U(n,x/2) polynomials.

Original entry on oeis.org

1, 3, 6, -3, 10, -12, 15, -30, 6, 21, -60, 30, 28, -105, 90, -10, 36, -168, 210, -60, 45, -252, 420, -210, 15, 55, -360, 756, -560, 105, 66, -495, 1260, -1260, 420, -21, 78, -660, 1980, -2520, 1260, -168, 91, -858, 2970, -4620, 3150, -756, 28, 105, -1092, 4290, -7920, 6930, -2520, 252, 120, -1365
Offset: 0

Views

Author

Wolfdieter Lang Apr 04 2007

Keywords

Comments

S2(n,x):=sum(S(n-k,x)*S1(k,x),k=0..n)= sum(a(n,m)*x^(n-2*m),m=0..floor(n/2)) with the first convolution S1(n,x) given by array A128502.
Row polynomials P2(n,x):= sum(a(n,m)*x^m,m=0..floor(n/2)) (increasing powers of x).

Examples

			n=4: [15,-30,6] stands for the polynomial S2(4,x) = 15*x^4-30*x^2+6 = 2*(S(4,x)*S1(0,x)+S(3,x)*S1(1,x))+S(2,x)*S1(2,x).
n=4:[15,-30,6] stands also for the row polynomial P2(4,x) = 15-30*x+6*x^2.
[1];[3];[6,-3];[10,-12];[15,-30,6];[21,-60,30];[28,-105,90,-10];...
		

Crossrefs

Row sums (signed array) give A128504. Unsigned row sums are A001628.
Cf. A128502 (k=1 convolution). A128505 (k=3 convolution).

Formula

a(n,m)= binomial(n-m+2,2)*binomial(n-m,m)*(-1)^m, m=0..floor(n/2), n>=0.
a(n,m)= binomial(m+2,2)*binomial(n-m+2,m+2)*(-1)^m, m=0..floor(n/2), n>=0.
G.f. for S2(n,x): 1/(1-x*z+z^2)^3.
G.f. for P2(n,x): 1/(1-z+x*z^2)^3

A147621 The 3rd Witt transform of A000292.

Original entry on oeis.org

0, 0, 0, 0, 4, 26, 120, 455, 1456, 4122, 10608, 25194, 55980, 117572, 235144, 450681, 832048, 1485800, 2575368, 4345965, 7158060, 11532402, 18209100, 28224105, 43008120, 64512240, 95365920, 139075245, 200268432, 284997384, 401107356
Offset: 0

Views

Author

R. J. Mathar, Nov 08 2008

Keywords

Comments

The 2nd Witt transform is essentially in A032094.

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 40); [0,0,0,0] cat Coefficients(R!( x^4*(2-x+2*x^2)*(2-2*x+9*x^2-2*x^3+2*x^4)/((1-x)^12*(1+x+x^2)^4) )); // G. C. Greubel, Oct 24 2022
    
  • Mathematica
    CoefficientList[Series[x^4(2*x^2 - x + 2)(2*x^4 - 2*x^3 + 9*x^2 - 2*x+2)/((1-x)^12 * (1 + x + x^2)^4), {x, 0, 40}],  x] (* Vincenzo Librandi  Dec 13 2012 *)
  • SageMath
    def A147621_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( x^4*(2-x+2*x^2)*(2-2*x+9*x^2-2*x^3+2*x^4)/((1-x)^12*(1+x+x^2)^4) ).list()
    A147621_list(40) # G. C. Greubel, Oct 24 2022

Formula

G.f.: x^4*(2-x+2*x^2)*(2-2*x+9*x^2-2*x^3+2*x^4)/((1-x)^12*(1+x+x^2)^4).
a(n) = (1/729)*(b(n) + c(n)), where b(n) = n*(n+3)*(n+6)*(3*n^8 +72*n^7 +618*n^6 + 2052*n^5 +207*n^4 -11772*n^3 -14268*n^2 +9648*n -232960)/492800 and c(n) = 9*A049347(n) +5*A049347(n-1) +9*(-1)^n*(A099254(n) -A099254(n-1)) -18(-1)^n*A128504(n) +27*(-1)^n*Sum_{k=0..n} A099254(n-k)*A099254(k-1). - G. C. Greubel, Oct 24 2022

A147618 The 3rd Witt transform of A000217.

Original entry on oeis.org

0, 0, 0, 0, 3, 15, 54, 165, 429, 999, 2145, 4290, 8100, 14586, 25194, 41985, 67830, 106590, 163431, 245157, 360525, 520749, 740025, 1036035, 1430703, 1950975, 2629575, 3506085, 4628052, 6052068, 7845255, 10086780, 12869340, 16301142
Offset: 0

Views

Author

R. J. Mathar, Nov 08 2008

Keywords

Comments

The 2nd Witt transform of A000217 is essentially in A032092.

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 30); [0,0,0,0] cat Coefficients(R!( 3*x^4*(1-x+3*x^2-x^3+x^4)/((1-x)^9*(1+x+x^2)^3) )); // G. C. Greubel, Oct 24 2022
    
  • Mathematica
    CoefficientList[Series[3*x^4*(1-x+3*x^2-x^3+x^4)/((1-x)^9*(1+x+x^2)^3), {x,0,40}], x] (* Vincenzo Librandi, Dec 13 2012 *)
  • SageMath
    def A147618_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 3*x^4*(1-x+3*x^2-x^3+x^4)/((1-x)^9*(1+x+x^2)^3) ).list()
    A147618_list(30) # G. C. Greubel, Oct 24 2022

Formula

G.f.: 3*x^4*(1-x+3*x^2-x^3+x^4)/((1-x)^9*(1+x+x^2)^3).
a(n) = (1/81)*(n*(n+3)*(3*n^6 +27*n^5 +45*n^4 -135*n^3 -288*n^2 +108*n -2000)/4480 +2*A049347(n) +A049347(n-1) +(-1)^n*(A099254(n) -2*A099254(n- 1)) -3*(-1)^n*(A128504(n) -2*A128504(n-1))). - G. C. Greubel, Oct 24 2022

A144701 Hankel transform of expansion of 1/c(x)^3, c(x) the g.f. of A000108.

Original entry on oeis.org

1, -9, 26, -25, -36, 133, -132, -81, 375, -374, -144, 806, -805, -225, 1480, -1479, -324, 2451, -2450, -441, 3773, -3772, -576, 5500, -5499, -729, 7686, -7685, -900, 10385, -10384, -1089, 13651, -13650, -1296, 17538, -17537
Offset: 0

Views

Author

Paul Barry, Sep 19 2008

Keywords

Comments

Hankel transform of A115142.

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1-x^2)*(1-5*x+x^2)/(1+x+x^2)^4 )); // G. C. Greubel, Jun 16 2022
    
  • Mathematica
    LinearRecurrence[{-4,-10,-16,-19,-16,-10,-4,-1}, {1,-9,26,-25,-36,133,-132,-81}, 40] (* G. C. Greubel, Jun 16 2022 *)
  • SageMath
    def A144701_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( (1-x^2)*(1-5*x+x^2)/(1+x+x^2)^4 ).list()
    A144701_list(40) # G. C. Greubel, Jun 16 2022

Formula

G.f.: (1+x)*(1-x)*(1-5*x+x^2)/(1+x+x^2)^4.
a(n) = (6 - 7*n - 9*n^2 - 2*n^3)*cos(2*Pi*n/3)/6 - sqrt(3)*(42 + 55*n + 21*n^2 + 2*n^3)*sin(2*Pi*n/3)/18.

A238988 Triangle T(n,k), read by rows, given by (1, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, -1, 0, 2, 1, -1, -1, 1, 2, 1, 0, -1, -2, 1, 3, 1, 1, 0, -4, -2, 3, 3, 1, 1, 1, -2, -4, -2, 3, 4, 1, 0, 1, 3, -2, -9, -2, 6, 4, 1, -1, 0, 6, 3, -9, -9, 0, 6, 5, 1, -1, -1, 3, 6, 3, -9, -15, 0, 10, 5, 1, 0, -1, -4, 3, 18, 3, -24, -15, 5, 10, 6, 1
Offset: 0

Views

Author

Philippe Deléham, Mar 07 2014

Keywords

Comments

T(n,0) = T(n+1,1) = A010892(n), T(n+2,2) = T(n+3,3) = A099254(n), T(n+4,4) = T(n+5,5) = A128504(n).
Triangle T(n,k) = A101950(n - floor((k+1)/2),floor(k/2)).

Examples

			Triangle begins:
1;
1, 1;
0, 1, 1;
-1, 0, 2, 1;
-1, -1, 1, 2, 1;
0, -1, -2, 1, 3, 1;
1, 0, -4, -2, 3, 3, 1;
1, 1, -2, -4, -2, 3, 4, 1;
0, 1, 3, -2, -9, -2, 6, 4, 1;
-1, 0, 6, 3, -9, -9, 0, 6, 5, 1;
-1, -1, 3, 6, 3, -9, -15, 0, 10, 5, 1;
0, -1, -4, 3, 18, 3, -24, -15, 5, 10, 6, 1;
1, 0, -8, -4, 18, 18, -6, -24, -20, 5, 15, 6, 1;
		

Crossrefs

Programs

  • Mathematica
    nmax=11; Flatten[CoefficientList[Series[CoefficientList[Series[(1 + x*y)/(1 - x + x^2 - x^2*y^2), {x, 0, nmax}], x], {y, 0, nmax}], y]] (* Indranil Ghosh, Mar 14 2017 *)

Formula

G.f.: (1 + x*y)/(1 - x + x^2 - x^2*y^2).
T(n,k) = T(n-1,k) + T(n-2,k-2) - T(n-2,k), T(0,0) = T(1,0) = T(1,1) = 1, T(n,k) = 0 if k<0 or if k>n.
Sum_{k = 0..n} T(n,k)*x^k = A000007(n), A010892(n), A040000(n), A105476(n+1) for x = -1, 0, 1, 2 respectively.

A281862 Riordan transform of the triangular number sequence A000217 with the Chebyshev S matrix A049310.

Original entry on oeis.org

0, 1, 3, 4, 1, -6, -11, -6, 9, 21, 14, -12, -34, -25, 15, 50, 39, -18, -69, -56, 21, 91, 76, -24, -116, -99, 27, 144, 125, -30, -175, -154, 33, 209, 186, -36, -246, -221, 39, 286, 259, -42, -329, -300, 45, 375
Offset: 0

Views

Author

Wolfdieter Lang, Feb 18 2017

Keywords

Comments

For the analogous sequence with the inverse S Riordan matrix A053121 see A189391.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x (1 + x^2)/(1 - x + x^2)^3, {x, 0, 45}], x] (* Michael De Vlieger, Feb 18 2017 *)

Formula

a(n) = Sum_{m=0..n} A049310(n,m)*A000217(m), n >= 0.
a(n) = b(n-1) + b(n-3), n >= 0 with b(-3) = b(-2) = b(-1) = 0 and b(n) = A128504(n) for n >= 0.
G.f.: (1/(1+x^2))*Tri(x/(1+x^2)), with Tri(x) = x/(1-x)^3 (g.f. of A000217).
G.f. x*(1 + x^2)/(1 - x + x^2)^3.
Showing 1-7 of 7 results.