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 11 results. Next

A143349 Triangle read by rows: A000012 * A054524 = A000012 * A051731 * A128407.

Original entry on oeis.org

1, 2, -1, 3, -1, -1, 4, -2, -1, 0, 5, -2, -1, 0, -1, 6, -3, -2, 0, -1, 1, 7, -3, -2, 0, -1, 1, -1, 8, -4, -2, 0, -1, 1, -1, 0, 9, -4, -3, 0, -1, 1, -1, 0, 0, 10, -5, -3, 0, -2, 1, -1, 0, 0, 1, 11, -5, -3, 0, -2, 1, -1, 0, 0, 1, -1, 12, -6, -4, 0, -2, 2, -1, 0, 0, 1, -1, 0, 13, -6, -4, 0, -2, 2, -1, 0, 0, 1, -1, 0, -1, 14, -7, -4, 0, -2, 2, -2, 0, 0, 1, -1, 0, -1, 1
Offset: 1

Views

Author

Gary W. Adamson, Aug 10 2008

Keywords

Comments

The triangle acts as a transform converting any sequence S(k) into a triangle with row sums = S(k). By way of example, begin with S(k), the primes: (2, 3, 5, 7, 11, ...). Add (0, 1, 2, 3, 4, ...) to the sequence getting (prime(n)+(n-1)) = (2, 4, 7, 10, 15, 18, 23, 36, 31, ...) = sequence Q(k). Then replace column 1 (1, 2, 3, ...) of triangle A143349 with sequence Q(k). This = triangle A143350 with row sums prime(n):
2;
4, -1;
7, -1, -1;
10, -2, -1, 0;
...
The A000012 multiplier takes partial sums of A054524 column terms. A051731 is the inverse Mobius transform and A128407 = an infinite lower triangular matrix with mu(n) in the main diagonal and the rest zeros.

Examples

			First few rows of the triangle:
   1;
   2, -1;
   3, -1, -1;
   4, -2, -1,  0;
   5, -2, -1,  0, -1;
   6, -3, -2,  0, -1,  1;
   7, -3, -2,  0, -1,  1, -1;
   8, -4, -2,  0, -1,  1, -1,  0;
   9, -4, -3,  0, -1,  1, -1,  0,  0;
  10, -5, -3,  0, -2,  1, -1,  0,  0,  1;
  11, -5, -3,  0, -2,  1, -1,  0,  0,  1, -1;
  12, -6, -4,  0, -2,  2, -1,  0,  0,  1, -1,  0;
  13, -6, -4,  0, -2,  2, -1,  0,  0,  1, -1,  0, -1;
  14, -7, -4,  0, -2,  2, -2,  0,  0,  1, -1,  0, -1,  1;
  ...
		

Crossrefs

Extensions

a(39) ff. corrected by Georg Fischer, Jun 05 2023

A140699 Triangle read by rows: A054524*A140256.

Original entry on oeis.org

1, 2, -1, 3, 0, -1, 2, -2, 0, 0, 5, 0, 0, 0, -1, 1, -3, -2, 0, 0, 1, 7, 0, 0, 0, 0, 0, -1, 2, -2, 0, 0, 0, 0, 0, 0, 3, 0, -3, 0, 0, 0, 0, 0, 0, 1, -5, 0, 0, -2, 0, 0, 0, 0, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, -1, -2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, -7, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 1, 1, 0, -5, 0, -3, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Mats O. Granvik and Gary W. Adamson, May 24 2008

Keywords

Comments

Row products are A140700. Similar to table A140256. Can perhaps be seen as taking the moebius function of A126988 times the mangoldt function of A126988.

Examples

			1;
2, -1;
3, 0, -1;
2, -2, 0, 0;
5, 0, 0, 0, -1;
1, -3, -2, 0, 0, 1;
7, 0, 0, 0, 0, 0, -1;
2, -2, 0, 0, 0, 0, 0, 0;
3, 0, -3, 0, 0, 0, 0, 0, 0;
1, -5, 0, 0, -2, 0, 0, 0, 0, 1;
11,0, 0, 0, 0, 0, 0, 0, 0, 0, -1;
		

Crossrefs

Formula

A253951 A partial double sum of integers: a(n) = Sum_{x=1..n} Sum_{y=1..n} T(x,y), where T is the matrix product: T = A051731*A127093*Transpose(A054524) and T(n,1)=0 (* stands for matrix multiplication).

Original entry on oeis.org

0, 1, 5, 9, 20, 23, 42, 52, 69, 77, 113, 119, 165, 177, 190, 214, 279, 291, 366, 379, 399, 422, 517, 533, 599, 625, 679, 701, 829, 846, 986, 1035, 1069, 1105, 1137, 1164, 1339, 1380, 1417, 1449, 1646, 1674, 1883, 1918, 1955, 2008, 2239, 2274, 2420, 2462, 2515, 2559, 2827, 2874, 2929
Offset: 1

Views

Author

Mats Granvik, Jan 20 2015

Keywords

Comments

a(n) ~ log(A003418(n))*n, based on the comment by Hans Havermann in A048272 referring to an argument by Gareth McCaughan.
The exact relation is: lim_{n->Infinity} log(A003418(k))*n = Sum_{x=1..n} Sum_{y=1..k} T(x,y), where T is the matrix product: T = A051731*A127093*Transpose(A054524) and T(n,1)=0.
Compare a(n) to round(log(A003418)*n)= 0, 1, 5, 10, 20, 25, 42, 54, 70, 78,...

Programs

  • Maple
    with(LinearAlgebra):
    N:= 200:
    A051731:= Matrix(N,N,(n,k) -> `if`(n mod k = 0, 1, 0),shape=triangular[lower]):
    A127093:= Matrix(N,N,(n,k) -> `if`(n mod k = 0, k, 0), shape=triangular[lower]):
    A054524T:= Matrix(N,N,(k,n) -> `if`(n mod k = 0, numtheory:-mobius(k),0), shape=triangular[upper]):
    T:= A051731 . A127093 . A054524T:
    a[1]:= 0:
    for n from 2 to N do
      a[n]:= a[n-1] + add(T[i,n],i=1..n) + add(T[n,j],j=2..n-1)
    od:
    seq(a[n],n=1..N); # Robert Israel, Jan 20 2015
  • Mathematica
    nn = 55;
    Z = Table[ If[ Mod[n, k] == 0, 1, 0], {n, nn}, {k, nn}];
    A = Table[ If[ Mod[n, k] == 0, k, 0], {n, nn}, {k, nn}];
    B = Table[ If[ Mod[n, k] == 0, MoebiusMu[k], 0], {n, nn}, {k, nn}];
    MatrixForm[T = Z.A.Transpose[B]];
    T[[All, 1]] = 0;
    a = Table[ Total[ T[[1 ;; n, 1 ;; n]], 2], {n, nn}]
    (* shows a graph *) Show[ ListLinePlot[a], ListLinePlot[ Accumulate[ MangoldtLambda[ Range[ nn]]]]]

Formula

a(n) = Sum_{x=1..n} Sum_{y=1..n} T(x,y), where T is the matrix product: T=A051731*A127093*Transpose(A054524) and T(n,1)=0. (* stands for matrix multiplication)

A128430 Triangle read by rows: A054524 * A000012.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Mar 02 2007

Keywords

Comments

Right border = mu(n), A008683. Row sums = A023900: (1, -1, -2, -1, -4, 2, -6, -1, ...). A054524 = A051731 * A128407.

Examples

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

Crossrefs

Formula

A054524 * A000012 as infinite lower triangular matrices.

A143352 Triangle read by rows, A051731 * A054524 = (A051731)^2 * A128407; 1<=k<=n.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Aug 10 2008

Keywords

Comments

Left border = d(n), A000010.
Right border = mu(n), A008683.
Row sums = 1.

Examples

			First few rows of the triangle =
1;
2, -1;
2, 0, -1;
3, -2, 0, 0;
2, 0, 0, 0, -1
4, -2, -2, 0, 0, 1;
2, 0, 0, 0, 0, 0, -1;
4, -3, 0, 0, 0, 0, 0, 0;
3, 0, -2, 0, 0, 0, 0, 0, 0;
4, -2, 0, 0, -2, 0, 0, 0, 0, 1;
...
		

Crossrefs

Formula

Triangle read by rows, A051731 * A054524 = (A051731)^2 * A128407; 1<=k<=n

A128407 Triangle read by rows: T(n,n) = mobius(n) on the diagonal, zero elsewhere.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Mar 01 2007

Keywords

Comments

A128407 * [1,2,3,...] = n*mu(n), A055615: (1, -2, -3, 0, -5, 6, -7, 0, ...). A051731 * A128407 = A054524. A128407 * A051731 = A128408.

Examples

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

Crossrefs

Cf. A051731, A128408, A008683 (row sums and diagonal), A054524.

Programs

  • Mathematica
    Table[PadLeft[{MoebiusMu[n]},n],{n,10}]//Flatten (* Harvey P. Dale, Dec 29 2021 *)

Formula

Infinite lower triangular matrix with mu(n), A008683, as the right border and the rest zeros.

Extensions

Name improved . - R. J. Mathar, Aug 03 2015

A128408 Triangle read by rows: A128407 * A051731 as infinite lower triangular matrices.

Original entry on oeis.org

1, -1, -1, -1, 0, -1, 0, 0, 0, 0, -1, 0, 0, 0, -1, 1, 1, 1, 0, 0, 1, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -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

Gary W. Adamson, Mar 01 2007

Keywords

Comments

Left and right borders = mu(n), A008683. Row sums = A008966: (1, -2, -2, 0, -2, 4, -2, 0, 0, 4, ...). A128408 * [1,2,3,...] = A063441: (1, -3, -4, 0, -6, 12, ...). A054524 = A051731 * A128407.

Examples

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

Crossrefs

Extensions

a(45) = 0 inserted and more terms from Georg Fischer, Jun 05 2023

A231425 The Schramm triangle: T(n,k) = f(gcd(n,k)), where f = Dirichlet inverse of Euler totient.

Original entry on oeis.org

1, 1, -1, 1, 1, -2, 1, -1, 1, -1, 1, 1, 1, 1, -4, 1, -1, -2, -1, 1, 2, 1, 1, 1, 1, 1, 1, -6, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -2, 1, 1, -2, 1, 1, -2, 1, -1, 1, -1, -4, -1, 1, -1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -10, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2
Offset: 1

Views

Author

Mats Granvik, Nov 19 2013

Keywords

Comments

When taking matrix powers of the reversed triangle it might be more interesting to start with the first term T(1,1) set to 0.
Three fundamental number theoretic sequences are found from this triangle. The first is the Dirichlet inverse of the Euler totient which are the entries themselves. The Greatest Common Divisor-Fourier transform described by Wolfgang Schramm gives the Möbius function times n =1, -2, -3, 0, ... = A055615, as follows:
1*cos(-2*k*Pi/n) = 1
1*cos(-2*k*Pi/n) -1*cos(-2*k*Pi/n) = -2
1*cos(-2*k*Pi/n) +1*cos(-2*k*Pi/n) -2*cos(-2*k*Pi/n) = -3
The two components in this GCD-Fourier triangle both sum to the sequence 1,0,0,0,0, ... A000007.
1 = 1
1 -1 = 0
1 +1 -2 = 0
...
cos(-2*k*Pi/n) = 1
cos(-2*k*Pi/n), cos(-2*k*Pi/n) = 0
cos(-2*k*Pi/n), cos(-2*k*Pi/n), cos(-2*k*Pi/n) = 0
...
This latter Fourier transform like triangle is also called the chaotic set by some authors.
The third arithmetic sequence is the von Mangoldt function that can be computed as sums with periods equal to rows in this triangle:
1
log(2) = Sum_{n>=0} (1/(n+1) -1/(n+2))
log(3) = Sum_{n>=0} (1/(n+1) +1/(n+2) -2/(n+3))
log(2) = Sum_{n>=0} (1/(n+1) -1/(n+2) +1/(n+3) -1/(n+4))
log(5) = Sum_{n>=0} (1/(n+1) +1/(n+2) +1/(n+3) +1/(n+4) -4/(n+5))
log(1) = Sum_{n>=0} (1/(n+1) -1/(n+2) -2/(n+3) -1/(n+4) +1/(n+5) +2/(n+6))
...
Also the matrix inverse of the reversal of this number triangle gives the all-ones sequence in the first column. Therefore this number triangle is a companion to A054524.
A subset and also a companion to this triangle in terms of Greatest Common Divisor Fourier transform is A054521, since from A054521 one gets the Mobius function while from this triangle one gets the Möbius function elementwise multiplied by the natural numbers.
The special polynomial found in A199514 is also the solution to the row-wise equations of the symmetric polynomial described in A199514 times the chaotic set or Greatest Common Divisor Fourier transform, so that A199514 is the solution.

Crossrefs

Programs

  • Mathematica
    Clear[nn, t, n, k]; nn = 12; t[n_, 1] = 1; t[1, k_] = 1;
    t[n_, k_] := t[n, k] = If[n >= k, -Sum[t[n - i, k], {i, 1, k - 1}], -Sum[t[k - i, n], {i, 1, n - 1}]]; Flatten[Table[Table[t[n, k], {k, 1, n}], {n, 1, nn}]]

Formula

T(n,k) = A023900(gcd(n,k)) for n >= k.

A140700 Row products of A140699.

Original entry on oeis.org

1, -2, -3, 0, -5, 6, -7, 0, 0, 10, -11, 0, -13, 14, 15, 0, -17, 0, -19, 0, 21, 22, -23, 0, 0, 26, 0, 0, -29, 30, -31, 0, 33, 34, 35, 0, -37, 38, 39, 0, -41, 42, -43, 0, 0, 46, -47, 0
Offset: 1

Views

Author

Mats O. Granvik and Gary W. Adamson, May 24 2008

Keywords

Comments

Primes have negative signs in a(n). Differs from A055615 at a(30) = 30.

Crossrefs

A366444 Triangle read by rows: T(n,k) = phi(n/k)*A023900(k) if k divides n, T(n,k) = 0 otherwise (n >= 1, 1 <= k <= n).

Original entry on oeis.org

1, 1, -1, 2, 0, -2, 2, -1, 0, -1, 4, 0, 0, 0, -4, 2, -2, -2, 0, 0, 2, 6, 0, 0, 0, 0, 0, -6, 4, -2, 0, -1, 0, 0, 0, -1, 6, 0, -4, 0, 0, 0, 0, 0, -2, 4, -4, 0, 0, -4, 0, 0, 0, 0, 4, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10, 4, -2, -4, -2, 0, 2, 0, 0, 0, 0, 0, 2
Offset: 1

Views

Author

Mats Granvik, Oct 12 2023

Keywords

Comments

Sum_{k=1..n} T(n,k) = A063524(n).

Examples

			{
{1}, = 1
{1, -1}, = 0
{2, 0, -2}, = 0
{2, -1, 0, -1}, = 0
{4, 0, 0, 0, -4}, = 0
{2, -2, -2, 0, 0, 2}, = 0
{6, 0, 0, 0, 0, 0, -6}, = 0
{4, -2, 0, -1, 0, 0, 0, -1}, = 0
{6, 0, -4, 0, 0, 0, 0, 0, -2}, = 0
{4, -4, 0, 0, -4, 0, 0, 0, 0, 4}, = 0
{10, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10}, = 0
{4, -2, -4, -2, 0, 2, 0, 0, 0, 0, 0, 2} = 0
}
		

Crossrefs

Programs

  • Mathematica
    nn = 12; g[n_] := DivisorSum[n, MoebiusMu[#] # &]; Flatten[Table[Table[If[Mod[n, k] == 0, EulerPhi[n/k]*g[k], 0], {k, 1, n}], {n, 1, nn}]]

Formula

T(n,k) = phi(n/k)*A023900(k) if k divides n, T(n,k) = 0 otherwise (n >= 1, 1 <= k <= n).
Showing 1-10 of 11 results. Next