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.

A129464 Second column (m=1) of triangle A129462 (v=2 member of a certain family).

Original entry on oeis.org

1, -2, -6, -48, -720, -17280, -604800, -29030400, -1828915200, -146313216000, -14485008384000, -1738201006080000, -248562743869440000, -41758540970065920000, -8142915489162854400000, -1824013069572479385600000, -465123332740982243328000000
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

See A129462 for the M. Bruschi et al. reference.

Crossrefs

Cf. A129462, A129465 (m=2), A129466 (m=3).
Cf. A229020.

Programs

  • Magma
    [1] cat [-Factorial(n-1)*Factorial(n+1): n in [1..30]]; // G. C. Greubel, Feb 08 2024
    
  • Maple
    A129464 := n -> `if`(n=0,1,-(n-1)!^2*n*(n+1)); # Peter Luschny, Oct 15 2010
  • Mathematica
    Table[If[n==0, 1, -(n-1)!*(n+1)!], {n,0,30}] (* G. C. Greubel, Feb 08 2024 *)
  • SageMath
    [1]+[-factorial(n-1)*factorial(n+1) for n in range(1,31)] # G. C. Greubel, Feb 08 2024

Formula

a(n) = A129462(n+1,1), n >= 0.
a(n) = -(n-1)!^2*n*(n+1), n > 0. - Peter Luschny, Oct 15 2010
From Amiram Eldar, May 17 2022: (Start)
Sum_{n>=1} 1/a(n) = -BesselI(2, 2) = -A229020.
Sum_{n>=1} (-1)^n/a(n) = BesselJ(2, 2). (End)

A129465 Third column (m=2) sequence of triangle A129462 (v=2 member of a certain family).

Original entry on oeis.org

1, 1, -4, -204, -7776, -358560, -20839680, -1516112640, -135920332800, -14772931891200, -1917601910784000, -293337284308992000, -52263416690343936000, -10734227287227924480000, -2518467729187335045120000, -669569466986357627289600000
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

See A129462 for the M. Bruschi et al. reference.

Crossrefs

Cf. A129462, A129464 (m=1), A129466(m=3).

Programs

  • Magma
    A129465:= func< n | n eq 0 select 1 else -Factorial(n)*Factorial(n+2)*(HarmonicNumber(n+2) -2) >;
    [A129465(n): n in [0..30]]; // G. C. Greubel, Feb 08 2024
    
  • Mathematica
    A129465[n_]:= If[n==0, 1, -n!*(n+2)!*(HarmonicNumber[n+2] -2)];
    Table[A129465[n], {n,0,30}] (* G. C. Greubel, Feb 08 2024 *)
  • SageMath
    def A129465(n): return 1 if (n==0) else -factorial(n)*factorial(n+2)*( harmonic_number(n+2) -2)
    [A129465(n) for n in range(31)] # G. C. Greubel, Feb 08 2024

Formula

a(n) = A129462(n+2, 2), n >= 0.
a(n) = (-1)*n!*(n+2)!*(HarmonicNumber(n+2) - 2), for n >= 1, otherwise a(0) = 1. - G. C. Greubel, Feb 08 2024

A129466 Fourth column (m=3) sequence of triangle A129462 (v=2 member of a certain family).

Original entry on oeis.org

1, 12, 208, 5208, 179688, 8175744, 472666752, 33625704960, 2858013642240, 281566521446400, 30978996781363200, 3583376917637529600, 374151199254884352000, 9777217907401555968000, -16608590925355066982400000, -10323797933882945175552000000
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

See A129462 for the M. Bruschi et al. reference.

Crossrefs

Cf. A129462, A129465 (m=2).

Programs

  • Magma
    function T(n, k) // T = A129462
      if k lt 0 or k gt n then return 0;
      elif n eq 0 then return 1;
      else return (2*(n-1)*(n-2)-1)*T(n-1, k) - ((n-1)*(n-3))^2*T(n-2, k) + T(n-1, k-1);
      end if;
    end function;
    A129466:= func< n | T(n+3,3) >;
    [A129466(n): n in [0..20]]; // G. C. Greubel, Feb 09 2024
    
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[n==0, 1, (2*(n-1)*(n-2) - 1)*T[n-1,k] -((n-1)*(n-3))^2*T[n-2,k] +T[n-1,k-1]]];(*T=A129462*)
    A129466[n_]:= T[n+3, 3];
    Table[A129466[n], {n,0,40}] (* G. C. Greubel, Feb 09 2024 *)
  • SageMath
    @CachedFunction
    def T(n, k): # T = A129462
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return (2*(n-1)*(n-2)-1)*T(n-1, k) - ((n-1)*(n-3))^2*T(n-2, k) + T(n-1, k-1)
    def A129466(n): return T(n+3,3)
    [A129466(n) for n in range(41)] # G. C. Greubel, Feb 09 2024

Formula

a(n) = A129462(n+3,3), n >= 0.

A129463 Row sums of triangle A129462 (v=2 member of a certain family).

Original entry on oeis.org

1, 0, -1, -4, -39, -680, -18425, -713820, -37390255, -2543067280, -217799766225, -22928327328500, -2909576503498775, -437960283393276600, -77145678498655849225, -15720035935018890359500, -3668950667796545284209375, -972327797466833893742228000
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

See A129462 for the M. Bruschi et al. reference.

Crossrefs

Cf. A129458 (row sums v=1 member), A129462.

Programs

  • Mathematica
    T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[n==0, 1, (2*(n-1)*(n-2) - 1)*T[n-1,k] -((n-1)*(n-3))^2*T[n-2,k] +T[n-1,k-1] ]]; (* T=A129462 *)
    A129463[n_]:= A129463[n]= Sum[T[n,k], {k,0,n}];
    Table[A129463[n], {n,0,40}] (* G. C. Greubel, Feb 08 2024 *)
  • SageMath
    @CachedFunction
    def T(n,k): # T = A129462
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return (2*(n-1)*(n-2)-1)*T(n-1,k) - ((n-1)*(n-3))^2*T(n-2,k) + T(n-1,k-1)
    def A129463(n): return sum(T(n,k) for k in range(n+1))
    [A129463(n) for n in range(41)] # G. C. Greubel, Feb 08 2024

Formula

a(n) = Sum_{k=0..n} A129462(n,k), n >= 0.
From Vaclav Kotesovec, Aug 24 2016: (Start)
a(n) = 2*(n-2)*(n-1)*a(n-1) - (n-3)^2*(n-1)^2*a(n-2).
a(n) ~ c * n^(2*n+(sqrt(5)-3)/2) / exp(2*n), where c = -2.3203776630375605070105975273368548459...
(End)

A129467 Orthogonal polynomials with all zeros integers from 2*A000217.

Original entry on oeis.org

1, 0, 1, 0, -2, 1, 0, 12, -8, 1, 0, -144, 108, -20, 1, 0, 2880, -2304, 508, -40, 1, 0, -86400, 72000, -17544, 1708, -70, 1, 0, 3628800, -3110400, 808848, -89280, 4648, -112, 1, 0, -203212800, 177811200, -48405888, 5808528, -349568, 10920, -168, 1, 0, 14631321600, -13005619200, 3663035136, -466619904, 30977424, -1135808, 23016, -240, 1
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

The row polynomials p(n,x) = Sum_{k=0..n} T(n,k)*x^k have the n integer zeros 2*A000217(j), j=0..n-1.
The row polynomials satisfy a three-term recurrence relation which qualify them as orthogonal polynomials w.r.t. some (as yet unknown) positive measure.
Column sequences (without leading zeros) give A000007, A010790(n-1)*(-1)^(n-1), A084915(n-1)*(-1)^(n-2), A130033 for m=0..3.
Apparently this is the triangle read by rows of Legendre-Stirling numbers of the first kind. See the Andrews-Gawronski-Littlejohn paper, table 2. The mirror version is the triangle A191936. - Omar E. Pol, Jan 10 2012

Examples

			Triangle starts:
  1;
  0,    1;
  0,   -2,     1;
  0,   12,    -8,   1;
  0, -144,   108, -20,   1;
  0, 2880, -2304, 508, -40,  1;
  ...
n=3: [0,12,-8,1]. p(3,x) = x*(12-8*x+x^2) = x*(x-2)*(x-6).
n=5: [0,2880,-2304,508,-40,1]. p(5,x) = x*(2880-2304*x+508*x^2-40*x^3 +x^4) = x*(x-2)*(x-6)*(x-12)*(x-20).
		

Crossrefs

Cf. A129462 (v=2 member), A129065 (v=1 member), A191936 (row reversed?).
Cf. A000217, A130031 (row sums), A130032 (unsigned row sums), A191936.
Column sequences (without leading zeros): A000007 (k=0), (-1)^(n-1)*A010790(n-1) (k=1), (-1)^n*A084915(n-1) (k=2), A130033 (k=3).
Cf. A008275.

Programs

  • Magma
    f:= func< n,k | (&+[Binomial(2*k+j,j)*StirlingFirst(2*n,2*k+j)*n^j: j in [0..2*(n-k)]]) >;
    function T(n,k) // T = A129467
      if k eq n then return 1;
      else return f(n,k) -  (&+[Binomial(j,2*(j-k))*T(n,j): j in [k+1..n]]);
    end if;
    end function;
    [[T(n,k): k in [0..n]]: n in [0..12]]; // G. C. Greubel, Feb 09 2024
    
  • Mathematica
    T[n_, k_, m_]:= T[n,k,m]= If[k<0 || k>n, 0, If[n==0, 1, (2*(n-1)*(n-m) -(m-1))*T[n-1,k,m] -((n-1)*(n-m-1))^2*T[n-2,k,m] +T[n-1,k-1,m]]]; (* T=A129467 *)
    Table[T[n,k,n], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 09 2024 *)
  • SageMath
    @CachedFunction
    def f(n,k): return sum(binomial(2*k+j,j)*(-1)^j*stirling_number1(2*n,2*k+j)*n^j for j in range(2*n-2*k+1))
    def T(n,k): # T = A129467
        if n==0: return 1
        else: return - sum(binomial(j,2*j-2*k)*T(n,j) for j in range(k+1,n+1)) + f(n,k)
    flatten([[T(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Feb 09 2024

Formula

Row polynomials p(n,x) = Product_{m=1..n} (x - m*(m-1)), n>=1, with p(0,x) = 1.
Row polynomials p(n,x) = p(n, v=n, x) with the recurrence: p(n,v,x) = (x + 2*(n-1)^2 - 2*(v-1)*(n-1) - v + 1)*p(n-1,v,x) - (n-1)^2*(n-1-v)^2*p(n-2,v,x) with p(-1,v,x) = 0 and p(0,v,x) = 1.
T(n, k) = [x^k] p(n, n, x), n >= k >= 0, otherwise 0.
T(n, k) = Sum_{j=0..2*(n-k)} ( binomial(2*k+j, j)*s(n,k)*n^j ) - Sum_{j=k+1..n} binomial(j, 2*(j-k))*T(n, j) (See Coffey and Lettington formula (4.7)). - G. C. Greubel, Feb 09 2024

A129065 Coefficients of the v=1 member of a family of certain orthogonal polynomials.

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 0, 12, 10, 1, 0, 144, 156, 28, 1, 0, 2880, 3696, 908, 60, 1, 0, 86400, 125280, 37896, 3508, 110, 1, 0, 3628800, 5780160, 2036592, 236472, 10528, 182, 1, 0, 203212800, 349090560, 138517632, 19022736, 1074176, 26600, 280, 1
Offset: 0

Views

Author

Wolfdieter Lang, May 04 2007

Keywords

Comments

For v >= 1 the orthogonal polynomials p(n,v,x) have v integer zeros k*(k-1), k = 1..v, for every n >= v.
Coefficients of p(n,v=1,x) (in the quoted Bruschi, et al., paper p(nu, n)(x) of eqs. (4) and (8a),(8b)) in increasing powers of x.
The v-family p(n,v,x) consists of characteristic polynomials of the tridiagonal M x M matrix V=V(M,v) with entries V_{m,n} given by v*(v-1) - (m-1)^2 - (v-m)^2 if n=m, m=1,...,M; (m-1)^2 if n=m-1, m=2,...,M; (v-m)^2 if n=m+1, m=1..M-1 and 0 else. p(n,v,x) := det(x*I_n - V(n,v) with the n-dimensional unit matrix I_n.
p(n,v=1,x) has, for every n >= 1, a zero for x=0, i.e., det(V(n,1))=0 for every n >= 1. This is obvious.
The column sequences give A000007, A010790, A129460, A129461 for m=0,1,2,3.

Examples

			Triangle begins:
  1;
  0,    1;
  0,    2,    1;
  0,   12,   10,   1;
  0,  144,  156,  28,   1;
  0, 2880, 3696, 908,  60,  1;
  ...
n=5,[0,2880,3696,908,60,1] stands for the polynomial x*(2880 + 3696*x + 908*x^2 + 60*x^3 + 1*x^4) with one zero 0 and some other four zeros.
Tridiagonal matrix V(5,1) = [[0,0,0,0,0], [1,-2,1,0,0], [0,4,-8,4,0], [0,0,9,-18,9], [0,0,0,16,-32]].
		

Crossrefs

Columns: A000007 (m=0), A010790, (m=1), A129460 (m=2), A129461 (m=3).
Cf. A129458 (row sums), A129462 (v=2 triangle).

Programs

  • Magma
    function T(n,k) // T = A129065
      if k lt 0 or k gt n then return 0;
      elif n eq 0 then return 1;
      else return 2*(n-1)^2*T(n-1,k) - 4*Binomial(n-1,2)^2*T(n-2,k) + T(n-1,k-1);
      end if;
    end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 07 2024
    
  • Mathematica
    nmax = 9; T[n_, m_] := T[n, m] = (-(n-2)^2)*(n-1)^2*T[n-2, m] + T[n-1, m-1] + 2*(n-1)^2*T[n-1, m]; T[n_, m_] /; n < m = 0; T[-1, ] = 0; T[0, 0] = 1; T[, -1] = 0; Flatten[Table[T[n, m], {n, 0, nmax}, {m, 0, n}]] (* Jean-François Alcover, Sep 26 2011, after recurrence *)
  • SageMath
    @CachedFunction
    def T(n,k): # T = A129065
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return 2*(n-1)^2*T(n-1,k) - 4*binomial(n-1,2)^2*T(n-2,k) + T(n-1,k-1)
    flatten([[T(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Feb 07 2024

Formula

T(n,m) = [x^m] p(n,1,x), n >= 0, with the three-term recurrence for orthogonal polynomial systems of the form p(n,v,x) = (x + 2*(n-1)^2 - 2*(v-1)*(n-1) - v+1)*p(n-1,v,x) - (n-1)^2*(n-1-v)^2*p(n-2,v,x), n >= 1; p(-1,v,x)=0 and p(0,v,x)=1. Put v=1 here.
Recurrence: T(n,m) = T(n-1,m-1) + (2*(n-1)^2 - 2*(v-1)*(n-1) - v + 1)*T(n-1,m) - ((n-1)^2*(n-1-v)^2)*T(n-2, m); T(n,m)=0 if n < m, T(-1,m):=0, T(0,0)=1, T(n,-1)=0. Put v=1 here.
Sum_{k=0..n} T(n, k) = A129458(n) (row sums).
Showing 1-6 of 6 results.