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.

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A069945 Let M_k be the k X k matrix M_k(i,j)=1/binomial(i+n,j); then a(n)=1/det(M_(n+1)).

Original entry on oeis.org

1, -6, -360, 252000, 2222640000, -258768639360000, -410299414270986240000, 9061429740221589431500800000, 2835046804394206618956825845760000000, -12733381268715468286016211650968992153600000000
Offset: 1

Views

Author

Benoit Cloitre, Apr 27 2002

Keywords

Comments

If k>n+1 det(M_k)=0

Crossrefs

Programs

  • Mathematica
    a[n_] := (-1)^Quotient[n, 2]/(Det[HilbertMatrix[n]] n!); Array[a, 10] (* Jean-François Alcover, Jul 06 2019 *)
  • PARI
    for(n=0,10,print1(1/matdet(matrix(n+1,n+1,i,j,1/binomial(i+n,j))),","))
    
  • Sage
    def A069945(n): return (-1)^(n//2)*mul(binomial(i,i//2) for i in (1..2*n-1))
    [A069945(i) for i in (1..11)] # Peter Luschny, Sep 18 2012

Formula

|a(n)| = det(M^(-1)), where M is an n X n matrix with M[i, j]=i/(i+j-1) (or j/(i+j-1)). |a(n)| = 1/det(HilbertMatrix(n))/n! = A005249(n)/n!. - Vladeta Jovovic, Jul 26 2003
|a(n)| = Product_{i=1..2n-1} binomial(i,floor(i/2)). - Peter Luschny, Sep 18 2012
|a(n)| = (Product_{i=1..2n-1} A056040(i))/n! = A163085(2*n-1)/n!. - Peter Luschny, Sep 18 2012

A101029 Denominator of partial sums of a certain series.

Original entry on oeis.org

1, 10, 70, 420, 4620, 60060, 60060, 408408, 7759752, 38798760, 892371480, 4461857400, 13385572200, 55454513400, 1719089915400, 3438179830800, 24067258815600, 890488576177200, 890488576177200, 36510031623265200, 1569931359800403600, 1569931359800403600, 73786773910618969200
Offset: 1

Views

Author

Wolfdieter Lang, Dec 17 2004

Keywords

Comments

The numerators are given in A101028.
One third of the denominator of the finite differences of the series of sums of all matrix elements of n X n Hilbert matrix M(i,j)=1/(i+j-1) (i,j = 1..n). - Alexander Adamchuk, Apr 11 2006

Examples

			n=2: HilbertMatrix[n,n]
   1  1/2
  1/2 1/3
so a(1) = (1/3)*denominator((1 + 1/2 + 1/2 + 1/3) - 1) = (1/3)*denominator(4/3) = 1.
The n X n Hilbert matrix begins:
   1  1/2 1/3 1/4 1/5  1/6  1/7  1/8 ...
  1/2 1/3 1/4 1/5 1/6  1/7  1/8  1/9 ...
  1/3 1/4 1/5 1/6 1/7  1/8  1/9  1/10 ...
  1/4 1/5 1/6 1/7 1/8  1/9  1/10 1/11 ...
  1/5 1/6 1/7 1/8 1/9  1/10 1/11 1/12 ...
  1/6 1/7 1/8 1/9 1/10 1/11 1/12 1/13 ...
		

Crossrefs

Cf. A101028 (numerators).

Programs

  • Mathematica
    Denominator[Table[Sum[1/(i + j - 1), {i, n}, {j, n}], {n,2, 27}]-Table[Sum[1/(i + j - 1), {i, n}, {j, n}], {n, 26}]]/3 (* Alexander Adamchuk, Apr 11 2006 *)
  • PARI
    a(n) = denominator(3*sum(k=1, n, 1/((2*k-1)*k*(2*k+1)))); \\ Michel Marcus, Feb 28 2022

Formula

a(n) = denominator(s(n)) with s(n) = 3*Sum_{k=1..n} 1/((2*k-1)*k*(2*k+1)). See A101028 for more information.
a(n) = (1/3)*denominator((Sum_{i=1..n+1} Sum_{j=1..n+1} 1/(i+j-1)) - (Sum_{i=1..n} Sum_{j=1..n} 1/(i+j-1))). a(n) = (1/3)*denominator(H(2*n+1) + H(2*n) - 2*H(n)), where H(n) = Sum_{k=1..n} 1/k is a harmonic number, H(n) = A001008/A002805. - Alexander Adamchuk, Apr 11 2006

Extensions

More terms from Michel Marcus, Feb 28 2022

A278840 a(n) = permanent M_n where M_n is the n X n matrix m(i,j) = A000041(i+j).

Original entry on oeis.org

1, 2, 19, 642, 58884, 13569779, 6931351962, 7532494931779, 16299546505518855, 67814300022651169814, 520884812091898994319805, 7206655416715261673779120809, 174009567319884878178189603283634, 7196671016523025599652036668556922867
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 29 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[{1, Table[Permanent[Table[PartitionsP[i+j], {i, 1, n}, {j, 1, n}]], {n, 1, 14}]}]

A278841 a(n) = permanent M_n where M_n is the n X n matrix m(i,j) = A000009(i+j).

Original entry on oeis.org

1, 1, 6, 65, 1737, 91359, 8755730, 1465091787, 420070484342, 194857695312573, 142349343815684947, 161388097061567486595, 276760372468557882285737, 707850058213409589011565269, 2654427644322345709705054800083
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 29 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[{1, Table[Permanent[Table[PartitionsQ[i+j], {i, 1, n}, {j, 1, n}]], {n, 1, 14}]}]

A061913 Numerators of the determinant of matrix (M(n) - H(n)), where H(n) is the n-th Hilbert matrix and M(n) is an n X n matrix with i,j-th entry i+j-1.

Original entry on oeis.org

1, 0, -9, 32, -337, 319, -347, 1609, -21569, 21911, -82601, 12211, -247249, 50003, -624457, 16297, -42209, 91127, -91159, 488749, -1773467, 1782853, -9429289, 6156767, -548213, 376169, -25705577, 732761, -84793, 343823, -60683401, 36941321, -89392129, 53762297, -1478431
Offset: 0

Views

Author

Asher Auel, May 20 2001

Keywords

Comments

The n-th Hilbert matrix is an n X n matrix with i,j-th entry 1/(i+j-1). Thus (M(n) - H(n)) has i,j-th entry (i+j-1) - 1/(i+j-1).

Crossrefs

Cf. A005249, A380297 (denominators).

Programs

  • Mathematica
    a[n_]:=Numerator[Det[Table[(i+j-1) - 1/(i+j-1),{i,n},{j,n}]]]; Join[{1},Array[a,34]] (* Stefano Spezia, Jan 19 2025 *)
  • PARI
    a(n) = numerator(matdet(matrix(n, n, i, j, (i+j-1) - 1/(i+j-1)))); \\ Michel Marcus, Jan 19 2025

Extensions

a(0) = 1 prepended by Stefano Spezia, Jan 19 2025

A061914 Let H_n = n-th Hilbert matrix; sequence gives 1 / ( det(H_n) * denominator(permanent(H_n)) ).

Original entry on oeis.org

1, 1, 1, 27, 567, 1, 1, 1, 7, 9, 5103, 1275989841, 992436543, 48629390607, 169706648853, 40257567, 63, 1, 7, 31, 1, 3969, 25865973, 117649, 117649, 16807, 49, 9, 81, 117369, 59049, 33480783, 930196594089, 4238886345135097131, 169560200598623521407
Offset: 1

Views

Author

Asher Auel, May 20 2001

Keywords

Crossrefs

Cf. A005249.

Programs

  • Maple
    with(linalg): seq(1/(denom(permanent(hilbert(n)))*det(hilbert(n))), n=1..16);
  • Mathematica
    Permanent[m_List] := With[{v = Array[x, Length[m]]}, Coefficient[Times @@ (m.v), Times @@ v]]; f[n_] := Block[{i = Table[1/(i + j - 1), {i, n}, {j, n}]}, 1/(Det[i]Denominator[Permanent[i]])]; Table[ f[n], {n, 1, 18}] (* Robert G. Wilson v, Feb 06 2004 *)
  • PARI
    permRWN(a)=n=matsize(a)[1]; if(n==1,return(a[1,1])); n1=n-1; sg=1; m=1; nc=0; in=vector(n); x=in; for(i=1,n,x[i]=a[i,n]-sum(j=1,n,a[i,j])/2); p=prod(i=1,n,x[i]); while(m,sg=-sg; j=1; if((nc%2)!=0,j++; while(in[j-1]==0,j++)); in[j]=1-in[j]; nc+=2*in[j]-1; m=nc!=in[n1]; z=2*in[j]-1; for(i=1,n,x[i]+=z*a[i,j]); p+=sg*prod(i=1,n,x[i])); return(2*(2*(n%2)-1)*p)
    for(n=1,23,a=mathilbert(n); print1(1/(matdet(a)*denominator(permRWN(a)))", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), May 10 2007
    
  • PARI
    for(n=1, 25, a=mathilbert(n); print1(1 / (matdet(a) * denominator(matpermanent(a)))", ")) \\ Vaclav Kotesovec, Aug 13 2021

Formula

a(n) = 1/(denominator(permanent(hilbert(n)))*det(hilbert(n))), where hilbert(n) denotes the n-th Hilbert matrix.

Extensions

a(18)-a(20) from Robert G. Wilson v, Feb 09 2004
a(21) from Eric W. Weisstein, Feb 19 2004
a(22) and a(23) from Herman Jamke (hermanjamke(AT)fastmail.fm), May 10 2007
a(24)-a(34) from Vaclav Kotesovec, Aug 14 2021
a(35) from Vaclav Kotesovec, Aug 16 2021

A076823 Array of coefficients of 1/det(M_n)*P(M_n) where P(M_n) is the characteristic polynomial of the n-th n X n Hilbert matrix M_n(i,j)=1/(i+j-1).

Original entry on oeis.org

-1, 1, 1, -16, 12, -1, 381, -3312, 2160, 1, -10496, 1603680, -10137600, 6048000, -1, 307505, -1022881200, 92708406000, -476703360000, 266716800000, 1, -9316560, 750409713900, -1242627237734400, 78981336366912000, -349935855575040000, 186313420339200000, -1
Offset: 1

Views

Author

Benoit Cloitre, Nov 27 2002

Keywords

Comments

Montgomery made a conjecture related to the largest eigenvalue of the Hilbert matrix (cf. Matthews link)

Examples

			Triangle begins:
  -1, 1;
  1, -16, 12;
  -1, 381, -3312, -2160;
  ...
		

Crossrefs

Cf. A005249.

Programs

  • Maple
    f:= proc(n) uses LinearAlgebra; local P,M;
      M:= HilbertMatrix(n);
      P:= CharacteristicPolynomial(M,t)/Determinant(M);
      seq(coeff(P,t,i),i=0..n)
    end proc:
    seq(f(n),n=1..10); # Robert Israel, May 07 2018
  • Mathematica
    row[n_] := Module[{P, M, x}, M = HilbertMatrix[n]; P = CharacteristicPolynomial[M, x]/Det[M]; (-1)^n CoefficientList[P, x]];
    Array[row, 10] // Flatten (* Jean-François Alcover, Jun 22 2020 *)
  • PARI
    vector(n+1,i,(polcoeff(charpoly(mathilbert(n))/matdet(mathilbert(n)),i-1))) \\ for the "n-th row"

Formula

T(n,0)=(-1)^n, T(n,n) = A005249(n). - Robert Israel, May 07 2018

A111194 Permanent of the inverse Hilbert matrix.

Original entry on oeis.org

1, 1, 84, 1397520, 5314794912000, 4855173934730716800000, 1090093558153665322315192780800000, 60907190511553979457004412118419080463155200000
Offset: 0

Views

Author

Roger Hui, Oct 22 2005

Keywords

Crossrefs

Cf. A005249 = determinant of inverse Hilbert matrix; and A092326 = (permanent/determinant) of inverse Hilbert matrix.

Programs

  • J
    NB. www.jsoftware.com
    H =: % @: >: @: (+/~) @: i. @ x:
    perm=: +/ .*
    perm@%.@H n
  • Mathematica
    Permanent[m_List] := With[{v = Array[x, Length[m]]}, Coefficient[Times @@ (m . v), Times @@ v]]; f[n_] := Block[{i = Inverse[Table[1/(i + j - 1), {i, n}, {j, n}]]}, Permanent[i]]; Table[ f[n], {n, 7}] (* Robert G. Wilson v, Oct 24 2005 *)

A135451 Triangular function from the characteristic polynomials of the inverse Hilbert matrices.

Original entry on oeis.org

1, 1, -1, 12, -16, 1, 2160, -3312, 381, -1, 6048000, -10137600, 1603680, -10496, 1, 266716800000, -476703360000, 92708406000, -1022881200, 307505, -1, 186313420339200000, -349935855575040000, 78981336366912000, -1242627237734400, 750409713900, -9316560, 1
Offset: 0

Views

Author

Roger L. Bagula, Dec 14 2007

Keywords

Comments

Triangle read by rows: for 0 <= k <= n, T(n,k) is the coefficient of lambda^k in det(H^(-1) - lambda I) where H is the n x n Hilbert matrix.
Row sums are: 1, 0, -3, -772, -2496415, -118300727696, -85882975706265059, -972835586209103886374316, -173520203650301344466515679407359, -489847775570499454780372858733881836257416, -21954569246037949585920541114453120558720536422853379

Examples

			{1},
{1, -1},
{12, -16, 1},
{2160, -3312, 381, -1},
{6048000, -10137600, 1603680, -10496, 1},
{266716800000, -476703360000, 92708406000, -1022881200, 307505, -1},
{186313420339200000, -349935855575040000, 78981336366912000, -1242627237734400, 750409713900, -9316560, 1}
		

Crossrefs

Cf. A005249.

Programs

  • Maple
    f:= proc(n) uses LinearAlgebra;
    local lambda, P,j;
    P:= CharacteristicPolynomial(HilbertMatrix(n),lambda)/Determinant(HilbertMatrix(n));
    seq(coeff(P,lambda,n-j),j=0..n);
    end proc:
    seq(f(n),n=0..10); # Robert Israel, Oct 05 2016
  • Mathematica
    << LinearAlgebra`MatrixManipulation`; a = Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[Inverse[HilbertMatrix[n]], x], x], {n, 1, 10}]]; Flatten[a]

Formula

t(n,m)=CoefficientList[CharacteristicPolynomial[Inverse[HilbertMatrix[n]], x], x]

Extensions

Edited by Robert Israel, Oct 05 2016

A174841 Determinant of the symmetric n X n matrix M_n where M_n(j,k) = n^abs(j-k).

Original entry on oeis.org

1, -3, 64, -3375, 331776, -52521875, 12230590464, -3938980639167, 1677721600000000, -913517247483640899, 619173642240000000000, -511324276025564512546607, 505488617542763051300683776
Offset: 1

Views

Author

Michel Lagneau, Mar 30 2010

Keywords

Examples

			a(4) = determinant(M_4) = -3375 where M_4 is the matrix
[ 1  4 16 64]
[ 4  1  4 16]
[16  4  1  4]
[64 16  4  1]
		

References

  • Jerry Glynn and Theodore Gray, The Beginner's Guide to Mathematica Version 4, Cambridge University Press, 2000, p. 76.

Crossrefs

Programs

  • Magma
    [ Determinant( SymmetricMatrix( &cat[ [ n^Abs(j-k): k in [1..j] ]: j in [1..n] ] ) ): n in [1..13] ]; // Klaus Brockhaus, Apr 16 2010
  • Maple
    for n from 1 to 20 do: x:=(1-n^2)^(n-1):print(x):od:

Formula

a(n) = (1-n^2)^(n-1).

Extensions

Edited by Klaus Brockhaus, Apr 16 2010
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