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 1-5 of 5 results.

A261356 Pyramid of coefficients in expansion of (1+x+2*y)^n.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 4, 1, 4, 4, 1, 3, 6, 3, 12, 12, 1, 6, 12, 8, 1, 4, 8, 6, 24, 24, 4, 24, 48, 32, 1, 8, 24, 32, 16, 1, 5, 10, 10, 40, 40, 10, 60, 120, 80, 5, 40, 120, 160, 80, 1, 10, 40, 80, 80, 32, 1, 6, 12, 15, 60, 60, 20, 120, 240, 160, 15, 120, 360, 480
Offset: 0

Views

Author

Dimitri Boscainos, Aug 16 2015

Keywords

Comments

T(n,j,k) is the number of lattice paths from (0,0,0) to (n,j,k) with steps (1,0,0), (1,1,0) and two kinds of steps (1,1,1).
The sum of the terms in each slice of the pyramid is 4^n (A000302).
The terms of the j-th row of the n-th slice of this pyramid are the sum of the terms in each row of the j-th triangle of the n-th slice of A189225. - Dimitri Boscainos, Aug 21 2015

Examples

			Here is the fourth (n=3) slice of the pyramid:
.....1......
...3   6....
..3  12  12.
.1  6  12  8
As an irregular triangle, rows begin:
1;
1, 1, 2;
1, 2, 4, 1, 4, 4;
1, 3, 6, 3, 12, 12, 1, 6, 12, 8;
...
		

Crossrefs

Programs

  • Maple
    p:= proc(i, j, k) option remember;
          if k<0 or i<0 or i>k or j<0 or j>i then 0
        elif {i, j, k}={0} then 1
        else p(i, j, k-1) +p(i-1, j, k-1) +2*p(i-1, j-1, k-1)
          fi
        end:
    seq(seq(seq(p(i, j, k), j=0..i), i=0..k), k=0..5);
    # Alois P. Heinz, Aug 20 2015
  • Mathematica
    p[i_, j_, k_] := p[i, j, k] = If[k < 0 || i < 0 || i > k || j < 0 || j > i, 0, If[Union@{i, j, k} == {0}, 1, p[i, j, k - 1] + p[i - 1, j, k - 1] + 2* p[i - 1, j - 1, k - 1]]];
    Table[Table[Table[p[i, j, k], {j, 0, i}], {i, 0, k}], {k, 0, 5}] // Flatten (* Jean-François Alcover, Sep 16 2023, after Alois P. Heinz *)

Formula

T(i+1,j,k) = 2*T(i,j-1,k-1)+T(i,j-1,k)+T(i,j,k); T(i,j,-1)=0,...; T(0,0,0)=1.
T(n,j,k) = 2^k*binomial(n,j)*binomial(j,k). - Dimitri Boscainos, Aug 21 2015

A261358 Pentatope of coefficients in expansion of (1 + x + y + 2*z)^n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 4, 1, 4, 4, 1, 3, 3, 6, 3, 6, 12, 3, 12, 12, 1, 3, 6, 3, 12, 12, 1, 6, 12, 8, 1, 4, 4, 8, 6, 12, 24, 6, 24, 24, 4, 12, 24, 12, 48, 48, 4, 24, 48, 32, 1, 4, 8, 6, 24, 24, 4, 24, 48, 32, 1, 8, 24, 32, 16, 1, 5, 5, 10, 10, 20, 40, 10, 40, 40, 10, 30, 60, 30, 120, 120, 30, 120, 240, 160, 5, 40, 120, 160, 80, 1, 5, 10, 10, 40, 40, 10, 60, 120, 80, 5, 40, 120, 160, 80, 1, 10, 40, 80, 80, 32
Offset: 0

Views

Author

Dimitri Boscainos, Aug 16 2015

Keywords

Comments

T(n,i,j,k) is the number of lattice paths from (0,0,0,0) to (n,i,j,k) with steps (1,0,0,0),(1,1,0,0),(1,1,1,0) and two kinds of steps (1,1,1,1).
The sum of the numbers in each cell of the pentatope is 5^n (A000351).
The sum of the antidiagonals of each triangle in each slice gives A261357. - Dimitri Boscainos, Aug 21 2015

Examples

			The 5th slice (n=4) of this 4D simplex starts at a(35). It comprises a 3D tetrahedron of 35 terms whose sum is 625. It is organized as follows:
.           1
.
.           4
.         4   8
.
.           6
.         12  24
.        6  24  24
.
.           4
.        12  24
.      12  48  48
.     4  24  48  32
.
.          1
.        4   8
.      6   24  24
.    4  24   48   32
.  1   8   24   32   16
		

Crossrefs

Programs

  • Maple
    p:= proc(i, j, k, l) option remember;
          if l<0 or j<0 or i<0 or i>l or j>i or k<0 or k>j then 0
        elif {i, j, k, l}={0} then 1
        else p(i, j, k, l-1) +p(i-1, j, k, l-1) +p(i-1, j-1, k, l-1)+2*p(i-1, j-1, k-1, l-1)
          fi
        end:
    seq(seq(seq(seq(p(i, j, k, l), k=0..j), j=0..i), i=0..l), l=0..5);
    # Adapted from Alois P. Heinz's Maple program for A261356

Formula

T(i+1,j,k,l) = 2*T(i,j-1,k-1,l-1) + T(i,j-1,k-1,l) + T(i,j-1,k,l) + T(i,j,k,l); a(i,j,k,-1)=0,...; a(0,0,0,0)=1.
T(n,i,j,k) = 2^k*binomial(n,i)*binomial(i,j)*binomial(j,k). - Dimitri Boscainos, Aug 21 2015

A261359 Pentatope of coefficients in expansion of (1 + x + 2*y + 2*z)^n.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 2, 4, 4, 1, 4, 4, 4, 8, 4, 1, 3, 6, 6, 3, 12, 12, 12, 24, 12, 1, 6, 6, 12, 24, 12, 8, 24, 24, 8, 1, 4, 8, 8, 6, 24, 24, 24, 48, 24, 4, 24, 24, 48, 96, 48, 32, 96, 96, 32, 1, 8, 8, 24, 48, 24, 32, 96, 96, 32, 16, 64, 96, 64, 16, 1, 5, 10, 10, 10, 40, 40, 40, 80, 40, 10, 60, 60, 120, 240, 120, 80, 240, 240, 80, 5, 40, 40, 120, 240, 120, 160, 480, 480, 160, 80, 320, 480, 320, 80, 1, 10, 10, 40, 80, 40, 80, 240, 240, 80, 80, 320, 480, 320, 80, 32, 160, 320, 320, 160, 32
Offset: 0

Views

Author

Dimitri Boscainos, Aug 16 2015

Keywords

Comments

T(n,i,j,k) is the number of lattice paths from (0,0,0,0) to (n,i,j,k) with steps (1,0,0,0), (1,1,0,0) and two kinds of steps (1,1,1,0) and (1,1,1,1).
The sum of the numbers in each cell of the pentatope is 6^n (A000400).

Examples

			The 5th slice (n=4) of this 4D simplex starts at a(35). It comprises a 3D tetrahedron of 35 terms whose sum is 1296. It is organized as follows:
.
.           1
.
.           4
.         8   8
.
.           6
.        24  24
.      24  48  24
.
.           4
.        24  24
.      48  96  48
.    32  96  96  32
.
.           1
.         8   8
.      24  48  24
.    32  96  96  32
.  16  64  96  64  16
		

Crossrefs

Programs

  • Maple
    p:= proc(i, j, k, l) option remember;
          if l<0 or j<0 or i<0 or i>l or j>i or k<0 or k>j then 0
        elif {i, j, k, l}={0} then 1
        else p(i, j, k, l-1) +p(i-1, j, k, l-1) +2*p(i-1, j-1, k, l-1)+2*p(i-1, j-1, k-1, l-1)
          fi
        end:
    seq(seq(seq(seq(p(i, j, k, l), k=0..j), j=0..i), i=0..l), l=0..5);
    # Adapted from Alois P. Heinz's Maple program for A261356
  • PARI
    lista(nn) = {for (n=0, nn, for (i=0, n, for (j=0, i, for (k=0, j, print1(2^j*binomial(n,i)*binomial(i,j)*binomial(j,k), ", ")););););} \\ Michel Marcus, Oct 07 2015

Formula

T(i+1,j,k,l) = 2*T(i,j-1,k-1,l-1) + 2*T(i,j-1,k-1,l) + T(i,j-1,k,l) + T(i,j,k,l); T(i,j,k,-1)=0,...; T(0,0,0,0)=1.
T(n,i,j,k) = 2^j*binomial(n,i)*binomial(i,j)*binomial(j,k). - Dimitri Boscainos, Aug 21 2015

A261360 Pentatope of coefficients in expansion of (1 + 2*x + 2*y + 2*z)^n.

Original entry on oeis.org

1, 1, 2, 2, 2, 1, 4, 4, 4, 4, 8, 8, 4, 8, 4, 1, 6, 6, 6, 12, 24, 24, 12, 24, 12, 8, 24, 24, 24, 48, 24, 8, 24, 24, 8, 1, 8, 8, 8, 24, 48, 48, 24, 48, 24, 32, 96, 96, 96, 192, 96, 32, 96, 96, 32, 16, 64, 64, 96, 192, 96, 64, 192, 192, 64, 16, 64, 96, 64, 96, 1, 10, 10, 10, 40, 80, 80, 40, 80, 40, 80, 240, 240, 240, 480, 240, 80, 240, 240, 80, 80, 320, 320, 480, 960, 480, 320, 960, 960, 320, 80, 320, 480, 320, 80, 32, 160, 160, 320, 640, 320, 320, 960, 960, 320, 160, 640, 960, 640, 160, 32, 160, 320, 320, 160, 32
Offset: 0

Views

Author

Dimitri Boscainos, Aug 16 2015

Keywords

Comments

T(n,i,j,k) is the number of lattice paths from (0,0,0,0) to (n,i,j,k) with steps (1,0,0,0) and two kinds of steps (1,1,0,0), (1,1,1,0) and (1,1,1,1).
The sum of the numbers in each cell of the pentatope is 7^n (A000420).

Examples

			The 5th slice (n=4) of this 4D simplex starts at a(35). It comprises a 3D tetrahedron of 35 terms whose sum is 2401. It is organized as follows:
.
.               1
.
.               8
.            8     8
.
.              24
.           48    48
.        24    48    24
.
.              32
.           96    96
.        96   192    96
.     32    96    96    32
.
.              16
.           64    64
.        96   192    96
.     64   192   192    64
.  16    64    96    64    16
		

Crossrefs

Programs

  • Maple
    p:= proc(i, j, k, l) option remember;
          if l<0 or j<0 or i<0 or i>l or j>i or k<0 or k>j then 0
        elif {i, j, k, l}={0} then 1
        else p(i, j, k, l-1) +2*p(i-1, j, k, l-1) +2*p(i-1, j-1, k, l-1)+2*p(i-1, j-1, k-1, l-1)
          fi
        end:
    seq(seq(seq(seq(p(i, j, k, l), k=0..j), j=0..i), i=0..l), l=0..5);
    # Adapted from Alois P. Heinz's Maple program for A261356
  • PARI
    lista(nn) = {for (n=0, nn, for (i=0, n, for (j=0, i, for (k=0, j, print1(2^i*binomial(n,i)*binomial(i,j)*binomial(j,k), ", ")););););} \\ Michel Marcus, Oct 07 2015

Formula

T(i+1,j,k,l) = 2*T(i,j-1,k-1,l-1) + 2*T(i,j-1,k-1,l) + 2*T(i,j-1,k,l) + T(i,j,k,l); T(i,j,k,-1)=0, ...; T(0,0,0,0)=1.
T(n,i,j,k) = 2^i*binomial(n,i)*binomial(i,j)*binomial(j,k). - Dimitri Boscainos, Aug 21 2015

A191358 Sequencing of all multinomial coefficients arranged in an s X r array of Pascal simplices P(s,r) and sequenced along the array's antidiagonals. Each P(s,r) is, in turn, a sequence of terms representing the coefficients of a_1,...,a_s in the expansion of (Sum_{i=1..s} a_i)^r with r starting at zero.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 4, 6, 4, 1, 1, 3, 3, 3, 6, 3, 1, 3, 3, 1, 1, 2, 2, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 10, 10, 5, 1, 1, 4, 4, 6, 12, 6, 4, 12, 12, 4, 1, 4, 6, 4, 1, 1, 3, 3, 3, 3, 6, 6, 3, 6, 3, 1, 3, 3, 3, 6, 3, 1, 3, 3, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 6, 15, 20, 15, 6, 1, 1, 5, 5, 10, 20, 10, 10, 30, 30, 10, 5, 20, 30, 20, 5, 1, 5, 10, 10, 5, 1, 1, 4, 4, 4, 6, 12, 12, 6, 12, 6, 4, 12, 12, 12, 24, 12, 4, 12, 12, 4, 1, 4, 4, 6, 12, 6, 4, 12, 12, 4, 1, 4, 6, 4, 1, 1, 3, 3, 3, 3, 3, 6, 6, 6, 3, 6, 6, 3, 6, 3, 1, 3, 3, 3, 3, 6, 6, 3, 6, 3, 1, 3, 3, 3, 6, 3, 1, 3, 3, 1, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 21, 35, 35, 21, 7, 1, 1, 6, 6, 15, 30, 15, 20, 60, 60, 20, 15, 60, 90, 60, 15, 6, 30, 60, 60, 30, 6, 1, 6, 15, 20, 15, 6, 1, 1, 5, 5, 5, 10, 20, 20, 10, 20, 10, 10, 30, 30, 30, 60, 30, 10, 30, 30, 10, 5, 20, 20, 30, 60, 30, 20, 60, 60, 20, 5, 20, 30, 20, 5, 1, 5, 5, 10, 20, 10, 10, 30, 30, 10, 5, 20, 30, 20, 5, 1, 5, 10, 10, 5, 1
Offset: 1

Views

Author

Frank M Jackson, May 31 2011

Keywords

Comments

The Pascal simplices P(s,r) are sequenced along the s*r array's antidiagonals as P(1,0), P(1,1), P(2,0), P(1,2), P(2,1), P(3,0), P(1,3), P(2,2), P(3,1), P(4,0), etc. P(2,3) is the sequence 1,3,3,1. P(2,r) = Pascal's triangle = A007318. P(3,r) = Pascal's tetrahedron = A046816. P(4,r) = Pascal's 4D simplex = A189225. Each P(s,r) has binomial(s-1+r, s-1) terms. The sum of its terms is s^r. The Pascal simplex P(s,r) starts at a(n) where n = 2^(s+r-1) + Sum_{p=0..s-2} binomial(s+r-1,p).

Examples

			The Pascal simplex P(4,5) for the coefficients of (a_1 + a_2 + a_3 + a_4)^5 is the sequence:
.......1
.......5
......5,5
.......10
.....20,20
....10,20,10
.......10
.....30,30
....30,60,30
..10,30,30,10
.......5
.....20,20
....30,60,30
..20,60,60,20
..5 ,20,30,20,5
.......1
......5,5
....10,20,10
..10,30,30,10
.5, 20,30,20,5
1,5, 10,10, 5,1
The sequence starts at a(293), it has 56 terms and the sum of its terms is 1024. It is also the 40th Pascal simplex in the sequence counting along the antidiagonals of the s*r array of Pascal simpices P(s,r).
Within the Pascal simplex P(4,5) the term S(5,3,2,1) = binomial(5,3)*binomial(3,2)*binomial(2,1) = 60.
		

Programs

  • Mathematica
    p[s_, r_] := (f[t_] := Binomial[k[t - 1], k[t]] f[t - 1]; f[1] = 1;
      dim = s; k[1] = r; list = {}; vstring[0] = "{k[``],0,k[``]},";
      Do[vstring[i] = ToString[StringForm[vstring[0], i + 1, i]], {i, 1, dim - 1}];
      dostring = "Do[AppendTo[list,f[dim]],]";
      Do[dostring =
        StringInsert[dostring, vstring[j], StringLength[dostring]], {j, dim - 1}];
      dostring = StringDrop[dostring, {StringLength[dostring] - 1}];
      ToExpression[StringReverse@StringReplace[StringReverse@dostring, ","->"", 1]];
      Flatten[List[list]])
    g[m_] := (For[h = 1; c = 1, c > 0, h++, c = m - h (h + 1)/2;
       a = m - h (h - 1)/2]; b = h - 1 - a; p[a, b])
    Flatten[Table[g[e], {e, 1, 40}]]

Formula

The Pascal simplex P(s,r) starts at a(n) where n = 2^(s+r-1) + Sum_{p=0..s-2} binomial(s+r-1,p). The individual terms within the Pascal simplex, S(r,t_1,t_2,...,t_(s-1)) are given by S(r,t_1,t_2,...,t_(s-1)) = binomial(r,t_1)*binomial(t_1,t_2)*...*binomial(t_(s-2),t_(s-1)).
Showing 1-5 of 5 results.