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 1-10 of 10 results.

A119508 Determinant of n X n matrix of first n^2 terms of Euler totient function phi (A000010).

Original entry on oeis.org

1, 0, -16, 80, -4640, -1696, -47290368, 778240, -1252408320, 827269120, -1883587535170560, -167527809024, -660985839681085440, -66300178824585216, -1744375183677849600, 29157688117836220727296, 5544673967679230591621398528, -134078707495836661579776
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(2) = 0 because of the singular matrix 0 =
|1 1|
|2 2|.
		

Crossrefs

Programs

  • Mathematica
    nmax = 20; Table[Det[Table[EulerPhi[k*(i-1) + j], {i, 1, k}, {j, 1, k}]], {k, 1, nmax}] (* Vaclav Kotesovec, Feb 24 2019 *)
    Table[Det[Partition[EulerPhi[Range[n^2]],n]],{n,20}] (* Harvey P. Dale, Jul 28 2021 *)

Extensions

More terms from Vaclav Kotesovec, Feb 24 2019

A119514 Determinant of n X n matrix of first n^2 squarefree numbers.

Original entry on oeis.org

1, -1, -4, -84, 64, 320, 1540, -4296, 22774, -11504, -5472, 13752, -18325, -4808916, 22766346, 5005440, 519618712, -216839949, -913585532, 4352326994, 15724880927, 0, -44298224496, 783852776697, -173267864064, -601092343023697, 26866456767483, 39073758546015
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Comments

The absolute value of a(1) through a(3) and a(5), are squares. None of the absolute values of a(1) through a(8) are themselves squarefree.

Examples

			a(2) = -1 =
|1 2|
|3 5|.
a(3) = -4 =
|.1..2..3|
|.5..6..7|
|10.11.13|.
		

Crossrefs

Programs

  • Mathematica
    s = Select[Range[1500], SquareFreeQ]; n = Length[s]; m = Floor[Sqrt[n]]; seq = {}; Do[mat = Partition[s[[1 ;; k^2]], k]; AppendTo[seq, Det[mat]], {k, 1, m}]; seq (* Amiram Eldar, Aug 23 2019 *)
    Module[{nn=30,sqfr},sqfr=Select[Range[2 nn^2],SquareFreeQ];Table[Det[ Partition[ Take[ sqfr,n^2],n]],{n,nn}]] (* Harvey P. Dale, Jul 09 2022 *)

Extensions

More terms from Amiram Eldar, Aug 23 2019

A119528 Determinant of n X n matrix of first n^2 number of trees with n unlabeled nodes (A000055).

Original entry on oeis.org

1, 0, 7, -7288, 210319661226, -28724163065553504725184, -17273218743083166095017987886925095168489136, -3262865955763797132157936566332771517266609360571691111615623236765760
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(3) = 7 =
|.1..1..1|
|.1..2..3|
|.6.11.23|.
		

Crossrefs

Extensions

More terms from Alois P. Heinz, Sep 26 2011

A119510 Determinant of n X n matrix of first n^2 terms of prime powers A000961.

Original entry on oeis.org

1, -2, 4, -18, 6, 1638, -592, 446088, 39036424, -284293536, -1842401824, 248900267136, -15845288960, -7495661063424, 759742256093184, -10356544812377088, -3243279301721283584, 12699358712830242816, 4118558014200840683520, -64593095335200293474304, -1944280313362776777097216
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(2) = -2 = |1 2|
            |3 4|.
a(3) = 4 = |1 2 3|
           |4 5 7|
           |8 9 11|.
		

Crossrefs

Extensions

More terms from Hugo Pfoertner, Sep 13 2024

A119512 Determinant of n X n matrix of first n^2 terms of A000020 number of primitive polynomials of degree n over GF(2).

Original entry on oeis.org

2, 2, 244, -80544, 2895473496576
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Comments

The initial 2 should probably be a 1, see: A011260. This would change all terms to: a(2) = 0 because of the singular determinant[1,1,2,2] = 0; a(3) = 52; a(4) = -34848; a(5) = -2211008492544.

Examples

			a(2) = 2 =
|2 1|
|2 2|.
		

Crossrefs

A119522 Determinant of n X n matrix of first n^2 nonzero terms of triangular numbers.

Original entry on oeis.org

1, -8, -27, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(3) = -27 =
|.1..3..6|
|10.15.21|
|28.36.45|.
a(4) = 0 because of the singular matrix 0 =
|.1...3...6..10|
|15..21..28..36|
|45..55..66..78|
|91.105.120.136|.
		

Crossrefs

Programs

  • Mathematica
    nmax = 100; Table[Det[Table[(k*(i-1) + j)*(k*(i-1) + j + 1)/2, {i, 1, k}, {j, 1, k}]], {k, 1, nmax}] (* Vaclav Kotesovec, Feb 24 2019 *)

Formula

a(n) = determinant of n X n matrix of first n^2 nonzero terms of A000217(k) for k>0. a(n) = determinant of n X n matrix of k*(k+1)/2 for k from 1 through n^2.

Extensions

More terms from Vaclav Kotesovec, Feb 24 2019

A119525 Determinant of n X n matrix of first n^2 nonzero terms of A000332 binomial coefficients binomial(n,4).

Original entry on oeis.org

1, -40, -8505, 9765625, 0
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Comments

a(5) = 5^10.

Examples

			a(3) = -8505 =
|..1...5..15|
|.35..70.126|
|210.330.495|.
a(4) = 0 because of the singular matrix 0 =
|.1...3...6..10|
|15..21..28..36|
|45..55..66..78|
|91.105.120.136|.
		

Crossrefs

A119527 Determinant of n X n matrix of first n^2 partition numbers (A000041).

Original entry on oeis.org

1, 1, -4, 40, -17570, 29277, 1612051490, -98797189506, 24519692392546611, -1102715711997300050, -4167252029989605007510429722, -29479989614260596083347544, 4174157347638693670019191622559426971168, 139672908285735171626083209102943170111074
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(3) = -4 =
|.1..1..2|
|.3..5..7|
|11.15.22|.
		

Crossrefs

Programs

  • Mathematica
    nmax = 15; Table[Det[Table[PartitionsP[k*(i-1) + j-1], {i, 1, k}, {j, 1, k}]], {k, 1, nmax}] (* Vaclav Kotesovec, Feb 24 2019 *)

Extensions

More terms from Vaclav Kotesovec, Feb 24 2019

A119530 Determinant of n X n matrix of first n^2 odious numbers: odd number of 1's in binary expansion (A000069).

Original entry on oeis.org

1, -1, 12, 0, -409, 0, 4144, 0, 5040, 0, 142291, 0, 29139, 0, 0, 0, 0, 0, -71577990, 0, 3815616, 0, -288128476, 0, -248768000, 0, 0, 0, -28714176, 0, 0, 0, 0, 0, -6040500480, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -795328048345114368
Offset: 1

Views

Author

Jonathan Vos Post, May 27 2006

Keywords

Examples

			a(3) = 12 =
  | 1  2  4|
  | 7  8 11|
  |13 14 16|.
a(4) = 0 because of the singular matrix 0 =
  | 1  2  4  7|
  | 8 11 13 14|
  |16 19 21 22|
  |25 26 28 31|.
a(6) = 0 because of the singular matrix whose lower right entry is 127.
		

Crossrefs

Programs

  • Mathematica
    nn=10000;With[{xa=Select[Range[nn],OddQ[DigitCount[#,2,1]]&]},Table[Det[ Partition[Take[xa,n^2],n]],{n,Floor[Sqrt[Length[xa]]]}]] (* Harvey P. Dale, Jun 28 2012 *)
  • PARI
    a(n)=matdet(matrix(n,n,i,j,k=(i-1)*n+j;2*k-1-hammingweight(k-1)%2)) \\ Charles R Greathouse IV, Mar 29 2013

Extensions

More terms from Harvey P. Dale, Jun 28 2012

A119537 Determinant of n X n matrices of first n^2 denumerants (A000115).

Original entry on oeis.org

1, 0, -3, -3, 0, -54, 343, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Jonathan Vos Post, May 28 2006

Keywords

Comments

Conjecture: a(n>7)=0. - Robert G. Wilson v, Jun 07 2006

Examples

			a(6) = -54 = -2 * 3^3. a(7) = 343 = 7^3.
a(8) = 0 because of the singular matrix 0 =
|..1...1...2...2...3...4...5...6|
|..7...8..10..11..13..14..16..18|
|.20..22..24..26..29..31..34..36|
|.39..42..45..48..51..54..58..61|
|.65..68..72..76..80..84..88..92|
|.97.101.106.110.115.120.125.130|
|135.140.146.151.157.162.168.174|
|180.186.192.198.205.211.218.224|.
		

Crossrefs

Programs

  • Mathematica
    clst = CoefficientList[ Series[1/((1 - x)(1 - x^2)(1 - x^5)), {x, 0, 105^2 - 1}], x];
    f[n_] := Det[ Partition[ Take[clst, n^2], n]];
    Array[f,100] (* Robert G. Wilson v, Jun 07 2006 *)

Formula

a(n) = determinant[A000115(k) from k=1 to n^2].

Extensions

More terms from Robert G. Wilson v, Jun 07 2006
Showing 1-10 of 10 results.