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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A160182 Triangle read by rows, 1 / ((-1)*A129184 * A051731 + I), I = Identity matrix.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 5, 2, 1, 1, 1, 6, 2, 1, 1, 1, 1, 10, 4, 2, 1, 1, 1, 1, 11, 4, 2, 1, 1, 1, 1, 1, 16, 6, 3, 2, 1, 1, 1, 1, 1, 19, 7, 4, 2, 1, 1, 1, 1, 1, 1, 26, 10, 5, 3, 2, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, May 03 2009

Keywords

Comments

Inverse mobius transform (A051731) * the triangle shifts row terms to the right deleting the right border, getting triangle A160183: (1; 2,1; 3,1,1; 5,2,1,1;...).

Examples

			First few rows of the triangle:
   1;
   1,  1;
   2,  1,  1;
   3,  1,  1,  1;
   5,  2,  1,  1,  1;
   6,  2,  1,  1,  1,  1;
  10,  4,  2,  1,  1,  1,  1;
  11,  4,  2,  1,  1,  1,  1,  1;
  16,  6,  3,  2,  1,  1,  1,  1,  1;
  19,  7,  4,  2,  1,  1,  1,  1,  1,  1;
  26, 10,  5,  3,  2,  1,  1,  1,  1,  1,  1;
  ...
		

Crossrefs

Row sums = A068336. Left border = A003238.

Programs

  • Maple
    A160182den := proc(n,k)
        a := add( A129184(n,i)*A051731(i,k),i=1..n) ;
        if n =k then
            -a+1 ;
        else
            -a;
        end if;
    end proc:
    N := 20 :
    M := Matrix(N,N) :
    for n from 1 to N do
    for k from 1 to N do
        M[n,k] := A160182den(n,k) ;
    end do:
    end do:
    MatrixInverse(M) ;  # R. J. Mathar, Aug 04 2015

Formula

Triangle read by rows, 1 / ((-1)*A129184 * A051731 + I), I = Identity matrix. The operations shift the inverse Mobius transform (A051731) down, changing the signs to (-1), then add I = (1,1,1,...) as the right border.

A174852 Triangle T(n,k) read by rows. T(1,1)=1, n>1 T(n,1)=A049240, k>1 T(n,k)=A051731.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Mats Granvik, Mar 31 2010

Keywords

Comments

Except for the first term the first column is equal to A049240. The rest of the table equals A051731. The first column = 0 when n is a square greater than 1.

Examples

			Table begins:
1,
1,1,
1,0,1,
0,1,0,1,
1,0,0,0,1,
1,1,1,0,0,1,
1,0,0,0,0,0,1,
1,1,0,1,0,0,0,1,
0,0,1,0,0,0,0,0,1,
1,1,0,0,1,0,0,0,0,1,
		

Crossrefs

Cf. A174854.

A177975 Square array T(n,k) read by antidiagonals up. Each column is the first column in the matrix inverse of a triangular matrix that is the k-th differences of A051731 in the column direction.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 2, 5, 3, 1, 0, 4, 7, 9, 4, 1, 0, 2, 14, 16, 14, 5, 1, 0, 6, 13, 34, 30, 20, 6, 1, 0, 4, 27, 43, 69, 50, 27, 7, 1, 0, 6, 26, 83, 107, 125, 77, 35, 8, 1, 0, 4, 39, 100, 209, 226, 209, 112, 44, 9, 1, 0, 10, 38, 155, 295, 461, 428, 329, 156, 54, 10, 1
Offset: 1

Views

Author

Mats Granvik, May 16 2010

Keywords

Comments

The first column in this array is the first column in A134540 which is the matrix inverse of A177978. The second column is the first column in A159905. The rows in this array are described by both binomial expressions and closed form polynomials.

Examples

			Table begins:
  1..1...1...1....1.....1.....1......1......1.......1.......1
  0..1...2...3....4.....5.....6......7......8.......9......10
  0..2...5...9...14....20....27.....35.....44......54......65
  0..2...7..16...30....50....77....112....156.....210.....275
  0..4..14..34...69...125...209....329....494.....714....1000
  0..2..13..43..107...226...428....749...1234....1938....2927
  0..6..27..83..209...461...923...1715...3002....5004....8007
  0..4..26.100..295...736..1632...3312...6270...11220...19162
  0..6..39.155..480..1266..2975...6399..12825...24255...43692
  0..4..38.182..641..1871..4789..11103..23807...47896...91367
  0.10..65.285.1000..3002..8007..19447..43757...92377..184755
  0..4..50.292.1209..4066.11837..30920..74139..165748..349438
  0.12..90.454.1819..6187.18563..50387.125969..293929..646645
  0..6..75.473.2166..8101.26202..75797.200479..492406.1136048
  0..8.100.636.2976.11482.38523.115915.319231..816421.1960190
  0..8.100.696.3546.14712.52548.167112.483879.1296064.3249312
		

Crossrefs

Column k=1..5 gives A063524, A000010, A007438, A117108, A117109.
Main diagonal gives A332470.

Programs

  • PARI
    T(n, k) = sumdiv(n, d, moebius(n/d)*binomial(d+k-2, d-1)); \\ Seiichi Manyama, Jun 12 2021

Formula

From Seiichi Manyama, Jun 12 2021: (Start)
G.f. of column k: Sum_{j>=1} mu(j) * x^j/(1 - x^j)^k.
T(n,k) = Sum_{d|n} mu(n/d) * binomial(d+k-2,d-1). (End)

A177978 Triangle T(n,k) read by rows: A051731(n,k) - A051731(n-1,k).

Original entry on oeis.org

1, 0, 1, 0, -1, 1, 0, 1, -1, 1, 0, -1, 0, -1, 1, 0, 1, 1, 0, -1, 1, 0, -1, -1, 0, 0, -1, 1, 0, 1, 0, 1, 0, 0, -1, 1, 0, -1, 1, -1, 0, 0, 0, -1, 1, 0, 1, -1, 0, 1, 0, 0, 0, -1, 1, 0, -1, 0, 0, -1, 0, 0, 0, 0, -1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, -1, 1, 0, -1, -1, -1, 0, -1, 0, 0, 0, 0, 0, -1, 1, 0, 1
Offset: 1

Views

Author

Mats Granvik, May 16 2010

Keywords

Comments

The recurrence for this triangle is similar to the recurrence in A177517. Cumulative column sums give table A051731.

Examples

			Triangle begins:
  1;
  0,  1;
  0, -1,  1;
  0,  1, -1,  1;
  0, -1,  0, -1,  1;
  0,  1,  1,  0, -1,  1;
  0, -1, -1,  0,  0, -1,  1;
  0,  1,  0,  1,  0,  0, -1,  1;
  0, -1,  1, -1,  0,  0,  0, -1,  1;
  0,  1, -1,  0,  1,  0,  0,  0, -1,  1;
  0, -1,  0,  0, -1,  0,  0,  0,  0, -1,  1;
  0,  1,  1,  1,  0,  1,  0,  0,  0,  0, -1,  1;
  0, -1, -1, -1,  0, -1,  0,  0,  0,  0,  0, -1,  1;
  0,  1,  0,  0,  0,  0,  1,  0,  0,  0,  0,  0, -1,  1;
		

Crossrefs

Matrix inverse of A134540. Cf. A177517.

Formula

T(n,1)=A000007, k > 1: T(n,k) = (Sum_{i=1..k-1} T(n-i,k-1)) - (Sum_{i=1..k-1} T(n-i,k)).

Extensions

Typo in sequence (erroneous comma) corrected by N. J. A. Sloane, May 22 2010
Edited by Mats Granvik, Dec 11 2010

A275345 Characteristic polynomials of a square matrix based on A051731 where A051731(1,N)=1 and A051731(N,N)=0 and where N=size of matrix, analogous to the Redheffer matrix.

Original entry on oeis.org

1, 1, -1, -1, -1, 1, -1, 0, 2, -1, 0, 0, 2, -3, 1, -1, 2, 1, -5, 4, -1, 1, -3, 5, -8, 9, -5, 1, -1, 4, -4, -5, 15, -14, 6, -1, 0, -1, 6, -17, 29, -31, 20, -7, 1, 0, 0, 2, -13, 36, -55, 50, -27, 8, -1, 1, -7, 23, -50, 84, -112, 112, -78, 35, -9, 1
Offset: 0

Views

Author

Mats Granvik, Jul 24 2016

Keywords

Comments

From Mats Granvik, Sep 30 2017: (Start)
Conjecture: The largest absolute value of the eigenvalues of these characteristic polynomials appear to have the same prime signature in the factorization of the matrix sizes N.
In other words: Let b(N) equal the sequence of the largest absolute values of the eigenvalues of the characteristic polynomials of the matrices of size N. b(N) is then a sequence of truncated eigenvalues starting:
b(N=1..infinity)
= 1.00000, 1.61803, 1.61803, 2.00000, 1.61803, 2.20557, 1.61803, 2.32472, 2.00000, 2.20557, 1.61803, 2.67170, 1.61803, 2.20557, 2.20557, 2.61803, 1.61803, 2.67170, 1.61803, 2.67170, 2.20557, 2.20557, 1.61803, 3.08032, 2.00000, 2.20557, 2.32472, 2.67170, 1.61803, 2.93796, 1.61803, 2.89055, 2.20557, 2.20557, 2.20557, 3.21878, 1.61803, 2.20557, 2.20557, 3.08032, 1.61803, 2.93796, 1.61803, 2.67170, 2.67170, 2.20557, 1.61803, 3.45341, 2.00000, 2.67170, 2.20557, 2.67170, 1.61803, 3.08032, 2.20557, 3.08032, 2.20557, 2.20557, 1.61803, 3.53392, 1.61803, 2.20557, 2.67170, ...
It then appears that for n = 1,2,3,4,5,...,infinity we have the table:
Prime signature: b(Axxxxxx(n)) = Largest abs(eigenvalue):
p^0 : b(1) = 1.0000000000000000000000000000...
p : b(A000040(n)) = 1.6180339887498949025257388711...
p^2 : b(A001248(n)) = 2.0000000000000000000000000000...
p*q : b(A006881(n)) = 2.2055694304005917238953315973...
p^3 : b(A030078(n)) = 2.3247179572447480566665944934...
p^2*q : b(A054753(n)) = 2.6716998816571604358216518448...
p^4 : b(A030514(n)) = 2.6180339887498917939012699207...
p^3*q : b(A065036(n)) = 3.0803227214906021558249449299...
p*q*r : b(A007304(n)) = 2.9379558827528557962693867011...
p^5 : b(A050997(n)) = 2.8905508875432590620846440288...
p^2*q^2 : b(A085986(n)) = 3.2187765853016649941764626419...
p^4*q : b(A178739(n)) = 3.4534111136673804054453285061...
p^2*q*r : b(A085987(n)) = 3.5339198574905377192578725953...
p^6 : b(A030516(n)) = 3.1478990357047909043330946587...
p^3*q^2 : b(A143610(n)) = 3.7022736187975437971431347250...
p^5*q : b(A178740(n)) = 3.8016448153137023524550386355...
p^3*q*r : b(A189975(n)) = 4.0600260453688532535920785448...
p^7 : b(A092759(n)) = 3.3935083220984414431597997463...
p^4*q^2 : b(A189988(n)) = 4.1453038440113498808159420150...
p^2*q^2*r: b(A179643(n)) = 4.2413382309993874486053755390...
p^6*q : b(A189987(n)) = 4.1311805192254587026923218218...
p*q*r*s : b(A046386(n)) = 3.8825338629275134572083061357...
...
b(Axxxxxx(1)) in the sequences above, is given by A025487.
(End)
First column in the coefficients of the characteristic polynomials is the Möbius function A008683.
Row sums of coefficients start: 0, -1, 0, 0, 0, 0, 0, 0, 0, ...
Third diagonal is a signed version of A000096.
Most of the eigenvalues are equal to 1. The number of eigenvalues equal to 1 are given by A075795 for n>1.
The first three of the eigenvalues above can be calculated as nested radicals. The fourth eigenvalue 2.205569430400590... minus 1 = 1.205569430400590... is also a nested radical.

Examples

			{
{ 1},
{ 1, -1},
{-1, -1,  1},
{-1,  0,  2,  -1},
{ 0,  0,  2,  -3,  1},
{-1,  2,  1,  -5,  4,   -1},
{ 1, -3,  5,  -8,  9,   -5,   1},
{-1,  4, -4,  -5, 15,  -14,   6,  -1},
{ 0, -1,  6, -17, 29,  -31,  20,  -7,  1},
{ 0,  0,  2, -13, 36,  -55,  50, -27,  8, -1},
{ 1, -7, 23, -50, 84, -112, 112, -78, 35, -9, 1}
}
		

Crossrefs

Programs

  • Mathematica
    Clear[x, AA, nn, s]; Monitor[AA = Flatten[Table[A = Table[Table[If[Mod[n, k] == 0, 1, 0], {k, 1, nn}], {n, 1, nn}]; MatrixForm[A]; a = A[[1, nn]]; A[[1, nn]] = A[[nn, nn]]; A[[nn, nn]] = a; CoefficientList[CharacteristicPolynomial[A, x], x], {nn, 1, 10}]], nn]

A127471 Triangle formed from the matrix product A051731 * A054522 of infinite lower triangular matrices, read by rows.

Original entry on oeis.org

1, 2, 1, 2, 0, 2, 3, 2, 0, 2, 2, 0, 0, 0, 4, 4, 2, 4, 0, 0, 2, 2, 0, 0, 0, 0, 0, 6, 4, 3, 0, 4, 0, 0, 0, 4, 3, 0, 4, 0, 0, 0, 0, 0, 6, 4, 2, 0, 0, 8, 0, 0, 0, 0, 4, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 6, 4, 6, 4, 0, 4, 0, 0, 0, 0, 0, 4, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12
Offset: 1

Views

Author

Gary W. Adamson, Jan 15 2007

Keywords

Comments

Left column = (1, 2, 2, 3, 2, 4, ...) = d(n), A000005; right border = (1, 1, 2, 2, 4, 2, 6, ...) = phi(n), A000010; row sums = (1, 3, 4, 7, 6, 12, ...) = sigma(n), A000203.

Examples

			First few rows of the triangle:
  1;
  2, 1;
  2, 0, 2;
  3, 2, 0, 2;
  2, 0, 0, 0, 4;
  4, 2, 4, 0, 0, 2;
  2, 0, 0, 0, 0, 0, 6;
  4, 3, 0, 4, 0, 0, 0, 4;
  3, 0, 4, 0, 0, 0, 0, 0, 6;
  4, 2, 0, 0, 8, 0, 0, 0, 0, 4;
  ...
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, Aug 11 2019
a(49) = 0 inserted and more terms from Georg Fischer, May 29 2023

A128184 A051731 * A097806.

Original entry on oeis.org

1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 1, 1, 2, 2, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 2, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 2, 1, 0, 1, 1, 0, 0, 0, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, Feb 17 2007

Keywords

Comments

Row sums = A114003: (1, 3, 3, 5, 3, 7, 3, 7, 5, 7, ...).

Examples

			First few rows of the triangle:
  1;
  2, 1;
  1, 1, 1;
  2, 1, 1, 1;
  1, 0, 0, 1, 1;
  2, 2, 1, 0, 1, 1;
  ...
		

Crossrefs

Formula

A051731 * A097806, (inverse Moebius transform of A097806).

A130106 A051731 * diagonalized matrix of A063659.

Original entry on oeis.org

1, 1, 2, 1, 0, 3, 1, 2, 0, 3, 1, 0, 0, 0, 5, 1, 2, 3, 0, 0, 6, 1, 0, 0, 0, 0, 0, 7, 1, 2, 0, 3, 0, 0, 0, 6, 1, 0, 3, 0, 0, 0, 0, 0, 8, 1, 2, 0, 0, 5, 0, 0, 0, 0, 10, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 1, 2, 3, 3, 0, 6, 0, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 1, 2, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 14
Offset: 1

Views

Author

Gary W. Adamson, May 07 2007

Keywords

Comments

Right border = A063659, (1, 2, 3, 3, 5, 6, 7, 6, 8, 10, ...), the Moebius transform of A001615: (1, 3, 4, 6, 6, 12, 8, 12, 12, ...).
A130106 * (1, 2, 3, ...) = A034676: (1, 5, 10, 17, 26, 50, 50, ...).
A034676^(-1) * (1,2,3,...) = 1/1, 1/2, 2/3, 2/3, 4/5, 2/6, 6/7, 4/6, 6/8, 4/10, ...; where the numerators = phi(n), A000010: (1, 1, 2, 2, 4, 2, 6, 4, ...); and the denominators = A063659, the right border of the triangle: (1, 2, 3, 3, 5, 6, 7, 8, 10, ...).

Examples

			First few rows of the triangle:
  1;
  1, 2;
  1, 0, 3;
  1, 2, 0, 3;
  1, 0, 0, 0, 5;
  1, 2, 3, 0, 0, 6;
  1, 0, 0, 0, 0, 0, 7,
  1, 2, 0, 3, 0, 0, 0, 6;
  1, 0, 3, 0, 0, 0, 0, 0, 8;
  ...
		

Crossrefs

Cf. A063659, A001615 (row sums), A051731, A000010.

Programs

  • Mathematica
    m = 14;
    A051731 = Table[If[Mod[n, k] == 0, 1, 0], {n, m}, {k, m}];
    A063659 = Table[Sum[MoebiusMu[GCD[n, k]]^2, {k, n}], {n, m}] // DiagonalMatrix;
    M = A051731.A063659;
    Table[M[[n, k]], {n, m}, {k, n}] // Flatten (* Jean-François Alcover, Jan 18 2020 *)

Formula

Inverse Moebius transform of an infinite lower triangular matrix with A063659, (1, 2, 3, 3, 5, 6, 7, 6, 8, 10, ...) in the main diagonal and the rest zeros.

Extensions

More terms from Jean-François Alcover, Jan 18 2020

A130160 A051731 * A130159 as a diagonalized matrix.

Original entry on oeis.org

1, 1, 1, 1, 0, 3, 1, 1, 0, 5, 1, 0, 0, 0, 7, 1, 1, 3, 0, 0, 6, 1, 0, 0, 0, 0, 0, 12, 1, 1, 0, 5, 0, 0, 0, 7, 1, 0, 3, 0, 0, 0, 0, 0, 12, 1, 1, 0, 0, 7, 0, 0, 0, 0, 10
Offset: 1

Views

Author

Gary W. Adamson, May 13 2007

Keywords

Comments

Right border = A130159, the Moebius transform of the Odious numbers, A000069: (1, 2, 4, 7, 8, 11, ...) = (1, 1, 3, 5, 7, 6, 12, ...). Row sums = A000069.

Examples

			First few rows of the triangle:
  1;
  1,  1;
  1,  0,  3;
  1,  1,  0,  5;
  1,  0,  0,  0,  7;
  1,  1,  3,  0,  0,  6;
  1,  0,  0,  0,  0,  0, 12;
  ...
		

Crossrefs

Formula

Inverse Moebius transform (A051731) of an infinite lower triangular matrix with A130159 in the main diagonal and rest zeros.

A130210 Triangle read by rows: matrix product A051731 * A130209.

Original entry on oeis.org

1, 1, 2, 1, 0, 2, 1, 2, 0, 3, 1, 0, 0, 0, 2, 1, 2, 2, 0, 0, 4, 1, 0, 0, 0, 0, 0, 2, 1, 2, 0, 3, 0, 0, 0, 4, 1, 0, 2, 0, 0, 0, 0, 0, 3, 1, 2, 0, 0, 2, 0, 0, 0, 0, 4, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 2, 3, 0, 4, 0, 0, 0, 0, 0, 6, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2
Offset: 1

Views

Author

Gary W. Adamson, May 17 2007

Keywords

Examples

			First few rows of the triangle are:
1;
1, 2;
1, 0, 2;
1, 2, 0, 3;
1, 0, 0, 0, 2;
1, 2, 2, 0, 0, 4;
1, 0, 0, 0, 0, 0, 2;
...
		

Crossrefs

Cf. A000005, A007425 (row sums).

Programs

Formula

Inverse Moebius transform of A130209.
T(n,n) = A000005(n).
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