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 28 results. Next

A133084 A007318 * A133080.

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 4, 3, 4, 1, 5, 4, 10, 4, 1, 6, 5, 20, 10, 6, 1, 7, 6, 35, 20, 21, 6, 1, 8, 7, 56, 35, 56, 21, 8, 1, 9, 8, 84, 56, 126, 56, 36, 8, 1, 10, 9, 120, 84, 252, 126, 120, 36, 10, 1, 11, 10, 165, 120, 462, 252, 330, 120, 55, 10, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 16 2007

Keywords

Comments

Row sums = A003945: (1, 3, 6, 12, 24, 48, 96, ...).
A133084 is jointly generated with A133567 as an array of coefficients of polynomials v(n,x): initially, u(1,x)=v(1,x)=1; for n>1, u(n,x)=u(n-1,x)+(x+1)*v(n-1)x and v(n,x)=x*u(n-1,x)+v(n-1,x)+1. See the Mathematica section. - Clark Kimberling, Feb 28 2012

Examples

			First few rows of the triangle:
  1;
  2,  1;
  3,  2,  1;
  4,  3,  4,  1;
  5,  4, 10,  4,  1;
  6,  5, 20, 10,  6,  1;
  7,  6, 35, 20, 21,  6,  1;
  ...
		

Crossrefs

Cf. A000292 (column 3 and 4), A000389 (column 5 and 6), A000580 (column 7).

Programs

  • Magma
    /* As triangle */ [[(1-(1+(-1)^k)/2 )*Binomial(n, k)+((1+(-1)^k)/2)*Binomial(n-1, k-1): k in [1..n]]: n in [1.. 11]]; // Vincenzo Librandi, Oct 21 2017
  • Maple
    A133084 := proc(n,k)
        add(binomial(n-1,i-1)*A133080(i,k),i=1..n) ;
    end proc: # R. J. Mathar, Jun 13 2025
  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := u[n - 1, x] + x*v[n - 1, x];
    v[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1;
    Table[Expand[u[n, x]], {n, 1, z/2}]
    Table[Expand[v[n, x]], {n, 1, z/2}]
    cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
    TableForm[cu]
    Flatten[%]   (* A133567 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]   (* A133084 *)
    (* Clark Kimberling, Feb 28 2012 *)
    T[n_, k_] := If[k == n, 1, (1  - (1 + (-1)^k)/2 )*Binomial[n, k] + ((1 + (-1)^k)/2)*Binomial[n - 1, k - 1]]; Table[T[n, k], {n, 1, 10}, {k, 1, n}] (* G. C. Greubel, Oct 21 2017 *)
  • PARI
    for(n=1,10, for(k=1,n, print1(if(k == n, 1, (1  - (1 + (-1)^k)/2 )*binomial(n, k) + ((1 + (-1)^k)/2)*binomial(n - 1, k - 1)), ", "))) \\ G. C. Greubel, Oct 21 2017
    

Formula

Binomial transform of triangle A133080.

A133081 An interpolation operator, companion to A133080.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Sep 09 2007

Keywords

Comments

A133081 * [1,2,3,...] = A133090: (1, 1, 5, 3, 9, 5, 13, 7, 17, ...).
A133080: diagonal and subdiagonal are switched.

Examples

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

Crossrefs

Cf. A133080, A133090, A040001 (row sums).

Programs

  • PARI
    row(n) = vector(n, k, if (k==n-1, 1, if (k==n, n%2)));
    lista(nn) = my(list=List()); for (n=1, nn, my(v=row(n)); for (k=1, #v, listput(list, v[k]))); Vec(list); \\ Michel Marcus, Mar 06 2022

Formula

Infinite lower triangular matrix, (1,0,1,0,...) in the main diagonal and (1,1,1,...) in the subdiagonal.

Extensions

More terms from Michel Marcus, Mar 06 2022

A133599 A097806 * A133080 * A007318.

Original entry on oeis.org

1, 3, 1, 3, 3, 1, 3, 7, 5, 1, 3, 9, 10, 5, 1, 3, 13, 22, 18, 7, 1, 3, 15, 31, 34, 21, 7, 1, 3, 19, 51, 75, 65, 33, 9, 1, 3, 21, 64, 111, 120, 83, 36, 9, 1, 3, 25, 92, 196, 266, 238, 140, 52, 11, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 18 2007

Keywords

Comments

Row sums = A133600: (1, 4, 7, 16, 28, 64, 112, ...).

Examples

			First few rows of the triangle:
  1;
  3,  1;
  3,  3,  1;
  3,  7,  5,  1;
  3,  9, 10,  5,  1;
  3, 13, 22, 18,  7,  1;
  ...
		

Crossrefs

Programs

Formula

A097806 * A133080 * A007318 as infinite lower triangular matrices, where A097806 = the pairwise operator and A133080 = an interpolation operator.

A133083 A000012 * A133080.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Sep 08 2007

Keywords

Comments

Row sums = A032766, congruent to {0,1} (mod 3): (1, 3, 4, 6, 7, 9, 10, ...).

Examples

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

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := If[k == n, 1, 1  + (1 - (-1)^k)/2 ]; Table[T[n, k], {n, 1, 10}, {k, 1, n}] (* G. C. Greubel, Oct 21 2017 *)
  • PARI
    for(n=1,10, for(k=1,n, print1(if(k==n, 1, 1 + (1-(-1)^k)/2), ", "))) \\ G. C. Greubel, Oct 21 2017

Formula

A000012 * A133080 as infinite lower triangular matrices.

A133087 A133080 * A007318.

Original entry on oeis.org

1, 2, 1, 1, 2, 1, 2, 5, 4, 1, 1, 4, 6, 4, 1, 2, 9, 16, 14, 6, 1, 1, 6, 15, 20, 15, 6, 1, 2, 13, 36, 55, 50, 27, 8, 1, 1, 8, 28, 56, 70, 56, 28, 8, 1, 2, 17, 64, 140, 196, 182, 112, 44, 10, 1
Offset: 0

Views

Author

Gary W. Adamson, Sep 08 2007

Keywords

Comments

Row sums = A084221: (1, 3, 4, 12, 16, 48, 64, 192, ...).
Subtriangle of (0, 2, -3/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 03 2012

Examples

			First few rows of the triangle:
  1;
  2,  1;
  1,  2,  1;
  2,  5,  4,  1;
  1,  4,  6,  4,  1;
  2,  9, 16, 14,  6,  1;
  1,  6, 15, 20, 15,  6,  1;
  2, 13, 36, 55, 50, 27,  8,  1;
  1,  8, 28, 56, 70, 56, 28,  8,  1;
  ...
Triangle (0, 2, -3/2, -1/2, 0, 0, 0, ...) DELTA (1, 0, -1, 0, 0, 0, ...) begins:
  1;
  0,  1;
  0,  2,  1;
  0,  1,  2,  1;
  0,  2,  5,  4,  1;
  0,  1,  4,  6,  4,  1;
  0,  2,  9, 16, 14,  6,  1;
  0,  1,  6, 15, 20, 15,  6,  1;
  0,  2, 13, 36, 55, 50, 27,  8,  1;
  0,  1,  8, 28, 56, 70, 56, 28,  8,  1;
  ...
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[CoefficientList[Series[(1 + 2*x + y*x)/(1 - (1 + y)^2*x^2), {x, 0, 10}, {y, 0, 10}], x], y] // Flatten (* G. C. Greubel, Oct 21 2017 *)

Formula

A133080 * A007318 as infinite lower triangular matrices.
G.f.: (1+2*x+y*x)/(1-(1+y)^2*x^2). - Philippe Deléham, Mar 03 2012
T(n,k) = T(n-2,k) + 2*T(n-2,k-1) + T(n-2,k-1), T(0,0) = 1, T(1,0) = 2, T(1,1) = 1. - Philippe Deléham, Mar 03 2012
Sum_{k=0..n} T(n,k)*x^k = A059841(n), A019590(n+1), A000034(n), A084221(n), A133125(n) for x = -2, -1, 0, 1, 2 respectively. - Philippe Deléham, Mar 03 2012

A133091 A133080 * A002260.

Original entry on oeis.org

1, 2, 2, 1, 2, 3, 2, 4, 6, 4, 1, 2, 3, 4, 5, 2, 4, 6, 8, 10, 6, 1, 2, 3, 4, 5, 6, 7, 2, 4, 6, 8, 10, 12, 14, 8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 2, 4, 6, 8, 10, 12, 14, 16, 18, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2
Offset: 1

Views

Author

Gary W. Adamson, Sep 09 2007

Keywords

Comments

Row sums = A133092: (1, 4, 6, 16, 15, 36, 28, ...).

Examples

			First few rows of the triangle:
  1;
  2,  2;
  1,  2,  3;
  2,  4,  6,  4;
  1,  2,  3,  4,  5;
  2,  4,  6,  8, 10,  6;
  1,  2,  3,  4,  5,  6,  7;
  ...
		

Crossrefs

Programs

  • Mathematica
    T[n_, n_] := n; T[n_, k_] := (2 - (1 - (-1)^n)/2)*k; Table[T[n, k], {n, 1, 10}, {k, 1, n}] (* G. C. Greubel, Oct 21 2017 *)
  • PARI
    for(n=1,10, for(k=1,n, print1(if(k==n, n,(2 - (1 - (-1)^n)/2)*k), ", "))) \\ G. C. Greubel, Oct 21 2017

Formula

A133080 * A002260 as infinite lower triangular matrices.
Odd n rows = (1,2,3,...,n). Even n rows = (2,4,6,...,n).

Extensions

Corrected and extended by Philippe Deléham, Mar 02 2012

A133093 A007318 * A097806 * A133080.

Original entry on oeis.org

1, 3, 1, 6, 3, 1, 10, 6, 5, 1, 15, 10, 15, 5, 1, 21, 15, 35, 15, 7, 1, 28, 21, 70, 35, 28, 7, 1, 36, 28, 126, 70, 84, 28, 9, 1, 45, 36, 210, 126, 210, 84, 45, 9, 1, 55, 45, 330, 210, 462, 210, 165, 45, 11, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 09 2007

Keywords

Comments

Row sums = A033484: (1, 4, 10, 22, 46, 94, ...).

Examples

			First few rows of the triangle:
   1;
   3,  1;
   6,  3,  1;
  10,  6,  5,  1;
  15, 10, 15,  5,  1;
  21, 15, 35, 15,  7,  1;
  28, 21, 70, 35, 28,  7,  1;
  ...
		

Crossrefs

Cf. A133080, A097806, A033484. Duplicate of A131110.

Formula

A007318 * A097806 * A133080 as infinite lower triangular matrices.
Binomial transform of an infinite lower triangular matrix with (1,1,1,...) in the main diagonal, (2,1,2,1,...) in the subdiagonal and (1,0,1,0,...) in the subsubdiagonal.

A133805 Triangle read by rows: A007318 * A133566 * A133080.

Original entry on oeis.org

1, 2, 1, 4, 3, 1, 7, 6, 4, 1, 11, 10, 11, 5, 1, 16, 15, 25, 15, 6, 1, 22, 21, 50, 35, 22, 7, 1, 29, 28, 91, 70, 63, 28, 8, 1, 37, 36, 154, 126, 154, 84, 37, 9, 1, 46, 45, 246, 210, 336, 210, 129, 45, 10, 1, 56, 55, 375, 330, 672, 462, 375, 165, 56, 11, 1, 67, 66, 550, 495, 1254, 924, 957, 495, 231, 66, 12, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 23 2007

Keywords

Comments

Row sums = A133806: (1, 3, 8, 18, 38, 78, 318, ...).
Left column = A000124.

Examples

			First few rows of the triangle:
   1;
   2,  1;
   4,  3,  1;
   7,  6,  4,  1;
  11, 10, 11,  5,  1;
  16, 15, 25, 15,  6,  1;
  22, 21, 50, 35, 22,  7,  1;
  29, 28, 91, 70, 63, 28,  8,  1;
  ...
		

Crossrefs

Formula

Binomial transform of (A133566 * A133080) where (A133566 * A133080) = an infinite lower triangular matrix with (1,1,1,...) in the main and subdiagonals and (1,0,1,0,1,...) in the subsubdiagonal.

Extensions

a(21) = 1 inserted and more terms from Georg Fischer, Jun 08 2023

A133094 A007318 * A133080 * A097806, as infinite lower triangular matrices.

Original entry on oeis.org

1, 3, 1, 5, 3, 1, 7, 7, 5, 1, 9, 14, 14, 5, 1, 11, 25, 30, 16, 7, 1, 13, 41, 55, 41, 27, 7, 1, 15, 63, 91, 91, 77, 29, 9, 1, 17, 92, 140, 182, 182, 92, 44, 9, 1, 19, 129, 204, 336, 378, 246, 156, 46, 11, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 09 2007

Keywords

Comments

Row sums give A133095.
Binomial transform of an infinite lower triangular matrix with (1,1,1,...) in the main diagonal, (2,1,2,1,...) in the subdiagonal and (0,1,0,1,...) in the subsubdiagonal.

Examples

			First few rows of the triangle:
   1;
   3,  1;
   5,  3,  1;
   7,  7,  5,  1;
   9, 14, 14,  5,  1;
  11, 25, 30, 16,  7,  1;
  13, 41, 55, 41, 27,  7,  1;
  ...
		

Crossrefs

A133113 A128174 * A007318 * A133080.

Original entry on oeis.org

1, 2, 1, 4, 2, 1, 6, 4, 4, 1, 9, 6, 11, 4, 1, 12, 9, 24, 11, 6, 1, 16, 12, 46, 24, 22, 6, 1, 20, 16, 80, 46, 62, 22, 8, 1, 25, 20, 130, 80, 148, 62, 37, 8, 1, 30, 25, 200, 130, 314, 148, 128, 37, 10, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 14 2007

Keywords

Comments

Row sums = 2^n - 1, A000225: (1, 3, 7, 15, 31, ...).

Examples

			First few rows of the triangle:
   1;
   2,  1;
   4,  2,  1;
   6,  4,  4,  1;
   9,  6, 11,  4,  1;
  12,  9, 24, 11,  6,  1;
  16, 12, 46, 24, 22,  6,  1;
  20, 16, 80, 46, 62, 22,  8,  1;
  ...
		

Crossrefs

Formula

A128174 * A007318 * A133080 as infinite lower triangular matrices.
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