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 1-6 of 6 results.

A176726 Numerator of a-sequence for Sheffer triangle A060081.

Original entry on oeis.org

1, 0, -2, 0, -32, 0, -704, 0, -54784, 0, -2610176, 0, -10976325632, 0, -52971659264, 0, -179326416191488, 0, -24309257264168960, 0, -69389116291423404032, 0, -8404514249426618810368, 0, -81520321871322828385550336, 0, -438807077783516207378333696, 0, -690781531822985516802849636352
Offset: 0

Views

Author

Wolfdieter Lang, Jul 14 2010

Keywords

Comments

The denominator sequence is A176727.
For a- and z-sequences for Sheffer triangles see the W. Lang link under A006232.

Examples

			Rationals A176726(n)/A176727(n): [1, 0, -2/3, 0, -32/15, 0, -704/21,0,...].
		

Crossrefs

A176728/A176729 z-sequence for triangle A060081.

Programs

  • Mathematica
    max = 29; s = x/Log[Sqrt[(1+x)/(1-x)]] + O[x]^max; CoefficientList[s, x] * Range[0, max-1]! // Numerator (* Jean-François Alcover, Oct 04 2016 *)

Formula

E.g.f. for rational a-sequence A176726/A176727: x/log(sqrt((1+x)/(1- x))).

A176727 Denominator of a-sequence for Sheffer triangle A060081.

Original entry on oeis.org

1, 1, 3, 1, 15, 1, 21, 1, 45, 1, 33, 1, 1365, 1, 45, 1, 765, 1, 399, 1, 3465, 1, 1035, 1, 20475, 1, 189, 1, 435, 1, 7161, 1, 58905, 1, 315, 1, 959595, 1, 117, 1, 20295, 1, 148995, 1, 108675, 1, 14805, 1, 2436525, 1, 65637, 1, 78705, 1, 21945, 1, 24795, 1, 531, 1, 85180095, 1, 135135
Offset: 0

Views

Author

Wolfdieter Lang, Jul 14 2010

Keywords

Comments

The numerator sequence is A176726.
For a- and z-sequences for Sheffer triangles see the W. Lang link under A006232.

Examples

			Rationals A176726(n)/A176727(n): [1, 0, -2/3, 0, -32/15, 0, -704/21,0,...].
		

Crossrefs

A176728/A176729 z-sequence for triangle A060081.

Programs

  • Mathematica
    max = 63; s = x/Log[Sqrt[(1+x)/(1-x)]] + O[x]^max; CoefficientList[s, x] * Range[0, max-1]! // Denominator (* Jean-François Alcover, Oct 04 2016 *)

Formula

E.g.f. for rational a-sequence A176726/A176727: x/log(sqrt((1+x)/(1- x))).

A176728 Numerator of z-sequence for Sheffer triangle A060081.

Original entry on oeis.org

1, 0, -1, 0, -17, 0, -1955, 0, -44089, 0, -4627969, 0, -10431967727, 0, -424734574531, 0, -187497600357613, 0, -263146180762981877, 0, -77335840394370605087, 0, -38414950218116664660463, 0, -95193934978797641162562791, 0, -1044549307308161782597280065, 0, -836232289988098415162220532417
Offset: 1

Views

Author

Wolfdieter Lang, Jul 14 2010

Keywords

Comments

The denominator sequence is A176729.
For a- and z-sequences for Sheffer triangles see the W. Lang link under A006232.

Examples

			Rationals A176728/A176729 with offset 0: [0,1/2,0,-1/4,0,-17/6,0,-1955/24,0,-44089/10,0,-4627969/12,... ].
		

Crossrefs

A176726/A176727 a-sequence for triangle A060081.

Formula

E.g.f. for rationals A176728/A176729: (1-sqrt(1-x^2))/log(sqrt((1+x)/(1-x))). For n=0 one has a(0)=0.

A176729 Denominator of z-sequence for Sheffer triangle A060081.

Original entry on oeis.org

1, 2, 1, 4, 1, 6, 1, 24, 1, 10, 1, 12, 1, 210, 1, 48, 1, 90, 1, 420, 1, 330, 1, 360, 1, 1638, 1, 28, 1, 30, 1, 7392, 1, 510, 1, 36, 1, 51870, 1, 840, 1, 6930, 1, 13860, 1, 4830, 1, 1008, 1, 99450, 1, 5148, 1, 2970, 1, 3192, 1, 870, 1, 180, 1, 2792790, 1, 137280, 1, 1530, 1, 5796
Offset: 1

Views

Author

Wolfdieter Lang, Jul 14 2010

Keywords

Comments

The numerator sequence is A176728.

Examples

			Rationals A176728/A176729 with offset 0: [0, 1/2, 0, -1/4, 0, -17/6, 0, -1955/24, 0, -44089/10, 0, -4627969/12, ... ].
		

Crossrefs

A176726/A176727 a-sequence for triangle A060081.

Formula

E.g.f. for rationals A176728/A176729: (1-sqrt(1-x^2))/log(sqrt((1+x)/(1-x))). For n=0 one has a(0)=1, hence A176728(0)/a(0)=0.

A060524 Triangle read by rows: T(n,k) = number of degree-n permutations with k odd cycles, k=0..n, n >= 0.

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 0, 5, 0, 1, 9, 0, 14, 0, 1, 0, 89, 0, 30, 0, 1, 225, 0, 439, 0, 55, 0, 1, 0, 3429, 0, 1519, 0, 91, 0, 1, 11025, 0, 24940, 0, 4214, 0, 140, 0, 1, 0, 230481, 0, 122156, 0, 10038, 0, 204, 0, 1, 893025, 0, 2250621, 0, 463490, 0, 21378, 0, 285, 0, 1, 0
Offset: 0

Views

Author

Vladeta Jovovic, Apr 01 2001

Keywords

Comments

The row polynomials t(n,x):=Sum_{k=0..n} T(n,k)*x^k satisfy the recurrence relation t(n,x) = x*t(n-1,x) + ((n-1)^2)*t(n-2,x); t(-1,x)=0, t(0,x)=1. - Wolfdieter Lang, see above.
This is an example of a Sheffer triangle (coefficient triangle for Sheffer polynomials). In the umbral calculus (see the Roman reference given under A048854) s(n,x) := Sum_{k=0..n} T(n,k)*x^k would be called Sheffer polynomials for (1/cosh(t),tanh(t)), which translates to the e.g.f. for column number k>=0 given by (1/sqrt(1-x^2))*((arctanh(x))^k)/k!. The e.g.f. given below is rewritten in this Sheffer context as (1/sqrt(1-x^2))*exp(y*log(sqrt((1+x)/(1-x))))= (1/sqrt(1-x^2))*exp(y*arctanh(x)). The rows of the Jabotinsky type triangle |A049218| provide the coefficients of the associated polynomials. - Wolfdieter Lang, Feb 24 2005
The solution of the differential-difference relation f(n+1,x)= (d/dx)f(n,x) + (n^2)*f(n-1,x), n >= 1, with inputs f(0,x) and f(1,x) = (d/dx)f(0,x) is f(n,x) = t(n,d_x)*f(0,x), with the differential operator d_x:=d/dx and the row polynomials t(n,x) defined above. This problem appears in a computation of thermo field dynamics where f(0,x)=1/cosh(x). See the triangle A060081. - Wolfdieter Lang, Feb 24 2005
The inverse of the Sheffer matrix T with elements T(n,k) is the Sheffer matrix A060081. - Wolfdieter Lang, Jul 22 2005
T(n,k)=0 if n-k= 1(mod 2), else T(n,k) = sum of M2(n,p), p from {1,...,A000041(n)} restricted to partitions with exactly k odd parts and any nonnegative number of even parts. For the M2-multinomial numbers in A-St order see A036039(n,p). - Wolfdieter Lang, Aug 07 2007

Examples

			Triangle begins:
  [1],
  [0, 1],
  [1, 0, 1],
  [0, 5, 0, 1],
  [9, 0, 14, 0, 1],
  [0, 89, 0, 30, 0, 1],
  [225, 0, 439, 0, 55, 0, 1],
  [0, 3429, 0, 1519, 0, 91, 0, 1],
  [11025, 0, 24940, 0, 4214, 0, 140, 0, 1],
  [0, 230481, 0, 122156, 0, 10038, 0, 204, 0, 1],
  [893025, 0, 2250621, 0, 463490, 0, 21378, 0, 285, 0, 1],
  [0, 23941125, 0, 14466221, 0, 1467290, 0, 41778, 0, 385, 0, 1],
  ...
Signed version begins:
  [1],
  [0, 1],
  [-1, 0, 1],
  [0, -5, 0, 1],
  [9, 0, -14, 0, 1],
  [0, 89, 0, -30, 0, 1],
  [-225, 0, 439, 0, -55, 0, 1],
  [0, -3429, 0, 1519, 0, -91, 0, 1],
  ...
From _Peter Bala_, Feb 23 2024: (Start)
Maple can verify the following series for Pi:
Row 1 polynomial R(1, x) = x:
Pi = 3 + 4*Sum_{n >= 1} (-1)^(n+1)/((2*n + 1)*R(1, 2*n)*R(1, 2*n+2)).
Row 3 polynomial R(3, x) = 5*x + x^3:
(3/2)^2 * Pi = 7 + 4*(3^4)*Sum_{n >= 1} (-1)^(n+1)/((2*n + 1)*R(3, 2*n)*R(3, 2*n+2)).
Row 5 polynomial R(5, x) = 89*x + 30*x^3 + x^5:
((3*5)/(2*4))^2 * Pi = 11 + 4*(3*5)^4*Sum_{n >= 1} (-1)^(n+1)/((2*n + 1)*R(5, 2*n)*R(5, 2*n+2)). (End)
		

Crossrefs

Cf. A060338, A060523, A094368, A028353 (col 1), A103916 (col 2), A103917 (col 3), A103918 (col 4).
Cf. A111594 (associated Sheffer polynomials), A142979, A142983.

Programs

  • Maple
    with(combinat):
    b:= proc(n, i) option remember; expand(`if`(n=0, 1, `if`(i<1, 0,
          add(multinomial(n, n-i*j, i$j)*(i-1)!^j/j!*b(n-i*j, i-1)*
          `if`(irem(i, 2)=1, x^j, 1), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n$2)):
    seq(T(n), n=0..12);  # Alois P. Heinz, Mar 09 2015
    # alternative
    A060524 := proc(n,k)
        option remember;
        if nR. J. Mathar, Jul 06 2023
  • Mathematica
    nn = 6; Range[0, nn]! CoefficientList[
       Series[(1 - x^2)^(-1/2) ((1 + x)/(1 - x))^(y/2), {x, 0, nn}], {x, y}] // Grid  (* Geoffrey Critzer, Aug 28 2012 *)

Formula

E.g.f.: (1+x)^((y-1)/2)/(1-x)^((y+1)/2).
T(n, k) = T(n-1, k-1) + ((n-1)^2)*T(n-2, k); T(-1, k):=0, T(n, -1):=0, T(0, 0)=1, T(n, k)=0 if nWolfdieter Lang, see above.
The Meixner polynomials defined by S_0(x)=1, S_1(x) = x; S_{n+1}(x) = x*S_n(x) - n^2*S_{n-1}(x) give a signed version of this triangle (cf. A060338). - N. J. A. Sloane, May 30 2013
From Peter Bala, Apr 10 2024: (Start)
The n-th row polynomial R(n, x) satisfies
(4*n + 2)*R(n, x) = (x + 1)*R(n, x+2) - (x - 1)*R(n, x-2).
Series for Pi involving the row polynomials R(n, x): for n >= 0 there holds
((2*n + 1)!!/(2^n*n!))^2 * Pi = (4*n + 3) + 4*((2*n + 1)!!^4) * Sum_{k >= 1} (-1)^(k+1)/((2*k + 1)*R(2*n+1, 2*k)*R(2*n+1, 2*k+2)). Cf. A142979 and A142983.
R(2*n, 0) = A001147(n)^2 = A001818(n); R(2*n+1, 0) = 0.
R(n, 1) = n! = A000142(n).
R(2*n, 2) = (4*n + 1)*A001147(n)^2 = (4*n + 1)*((2*n)!/(2^n*n!))^2;
R(2*n+1, 2) = 2*A001447(n+1)^2 = 2*(2*n + 1)!^2/(n!^2*4^n).
R(n, 3) = (2*n + 1)*n! = A007680(n). (End)

A111593 Triangle of tanh numbers.

Original entry on oeis.org

1, 0, 1, 0, 0, 1, 0, -2, 0, 1, 0, 0, -8, 0, 1, 0, 16, 0, -20, 0, 1, 0, 0, 136, 0, -40, 0, 1, 0, -272, 0, 616, 0, -70, 0, 1, 0, 0, -3968, 0, 2016, 0, -112, 0, 1, 0, 7936, 0, -28160, 0, 5376, 0, -168, 0, 1, 0, 0, 176896, 0, -135680, 0, 12432, 0, -240, 0, 1, 0, -353792, 0, 1805056, 0, -508640, 0, 25872
Offset: 0

Views

Author

Wolfdieter Lang, Aug 23 2005

Keywords

Comments

Sheffer triangle associated to Sheffer triangle A060081.
For Sheffer triangles (matrices) see the explanation and S. Roman reference given under A048854.
In the umbral calculus (see the S. Roman reference) this triangle would be called associated for (1,arctanh(y)).
Without the n=0 row and m=0 column and unsigned, this is the Jabotinsky triangle A059419.
The inverse matrix of A with elements a(n,m), n,m>=0, is A111594.
The row polynomials p(n,x):=sum(a(n,m)*x^m,m=0..n), together with the row polynomials s(n,x) of A060081, satisfy the exponential (or binomial) convolution identity s(n,x+y) = sum(binomial(n,k)*s(k,x)*p(n-k,y),k=0..n), n>=0.
The row polynomials p(n,x) (defined above) have e.g.f. exp(x*tanh(y)).
Exponential Riordan array [1, tanh(x)], inverse of [1, arctanh(x)] which is A111594. - Paul Barry, May 30 2010
Also the Bell transform of A155585(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016

Examples

			Binomial convolution of row polynomials: p(3,x)= -2*x+x^3; p(2,x)=x^2, p(1,x)= x, p(0,x)= 1, together with those from A060081:
s(3,x)= -5*x+x^3; s(2,x)= -1+x^2, s(1,x)= x, s(0,x)= 1;
therefore -5*(x+y)+(x+y)^3 = s(3,x+y) = 1*s(0,x)*p(3,y) + 3*s(1,x)*p(2,y) + 3*s(2,x)*p(1,y) +1*s(3,x)*p(0,y) = -2*y+y^3 + 3*x*y^2 + 3*(-1+x^2)*y + (-5*x+x^3).
From _Paul Barry_, May 30 2010: (Start)
Triangle begins:
  1;
  0,     1;
  0,     0,     1;
  0,    -2,     0,     1;
  0,     0,    -8,     0,     1;
  0,    16,     0,   -20,     0,     1;
  0,     0,   136,     0,   -40,     0,     1;
  0,  -272,     0,   616,     0,   -70,     0,     1;
  0,     0, -3968,     0,  2016,     0,  -112,     0,     1;
Production matrix begins:
  0,   1;
  0,   0,   1;
  0,  -2,   0,   1;
  0,   0,  -6,   0,   1;
  0,   0,   0, -12,   0,   1;
  0,   0,   0,   0, -20,   0,   1;
  0,   0,   0,   0,   0, -30,   0,   1;
  0,   0,   0,   0,   0,   0, -42,   0,   1;
  0,   0,   0,   0,   0,   0,   0, -56,   0,   1; (End)
		

Crossrefs

Row sums: A003723. Unsigned row sums: A006229.
Cf. A002378.

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    BellMatrix(n -> 2^(n+1)*euler(n+1, 1), 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    t[0, 0] = 1; t[n_, m_] := Sum[ Binomial[k+m-1, m-1]*(k+m)!*(-1)^(k)*2^(n-k-m)*StirlingS2[n, k+m], {k, 0, n-m}]/m!; Table[t[n, m], {n, 0, 11}, {m, 0, n}] // Flatten (* Jean-François Alcover, Jul 05 2013, after Vladimir Kruchinin *)
    BellMatrix[f_Function, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    rows = 12;
    M = BellMatrix[2^(#+1)*EulerE[#+1, 1]&, rows];
    Table[M[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 23 2018, after Peter Luschny *)
  • Maxima
    T(n,m):=if n=0 and m=0 then 1 else sum(binomial(k+m-1,m-1)*(k+m)!*(-1)^(k)*2^(n-k-m)*stirling2(n,k+m),k,0,n-m)/m!; /* Vladimir Kruchinin, Jun 09 2011 */
    
  • Sage
    # uses[riordan_array from A256893]
    riordan_array(1, tanh(x), 9, exp=true) # Peter Luschny, Apr 19 2015

Formula

E.g.f. for column m>=0: ((tanh(x))^m)/m!.
a(n, m) = coefficient of x^n of ((tanh(x))^m)/m!, n>=m>=0, else 0.
a(n, m) = a(n-1, m-1) - (m+1)*m*a(n-1, m+1), a(n, -1):=0, a(0, 0)=1, a(n, m)=0 for n
T(n,m) = (Sum_{k=0..n-m} binomial(k+m-1,m-1)*(k+m)!*(-1)^k*2^(n-k-m)*stirling2(n,k+m))/m!, T(0,0)=1. - Vladimir Kruchinin, Jun 09 2011
With e.g.f. exp(x*tanh(t)) = sum(n>= 0, P(n,x)*t^n/n!), the lowering operator is L = arctanh(d/dx) = d/dx + (1/3)(d/dx)^3 + (1/5)(d/dx)^5 + ..., and the raising operator is R = x [1 - (d/dx)^2], where L P(n,x) = n P(n-1,x) and R P(n,x) = P(n+1,x), since the sequence is a binomial Sheffer sequence. - Tom Copeland, Oct 01 2015
The raising operator R = x - x D^2 in matrix form acting on an o.g.f. (formal power series) is the transpose of the production matrix M below. The linear term x is the diagonal of ones after transposition. The other transposed diagonal (A002378) comes from -x D^2 x^n = -n * (n-1) x^(n-1). Then P(n,x) = (1,x,x^2,..) M^n (1,0,0,..)^T. - Tom Copeland, Aug 17 2016
Showing 1-6 of 6 results.