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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A193822 Mirror of the triangle A193821.

Original entry on oeis.org

1, 1, 1, 3, 3, 2, 9, 9, 8, 4, 27, 27, 26, 20, 8, 81, 81, 80, 72, 48, 16, 243, 243, 242, 232, 192, 112, 32, 729, 729, 728, 716, 656, 496, 256, 64, 2187, 2187, 2186, 2172, 2088, 1808, 1248, 576, 128, 6561, 6561, 6560, 6544, 6432, 5984, 4864, 3072, 1280, 256
Offset: 0

Views

Author

Clark Kimberling, Aug 06 2011

Keywords

Comments

A193822 is obtained by reversing the rows of the triangle A193821.

Examples

			First six rows:
1
1....1
3....3....2
9....9....8.....4
27...27...26....20...8
81...81...80....72...48...16
		

Crossrefs

Programs

  • Mathematica
    p[n_, x_] := (a*x + b)^n
    q[0, x_] := 1
    q[n_, x_] := x*q[n - 1, x] + 1; q[n_, 0] := q[n, x] /. x -> 0;
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]   (* A193821 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193822 *)

Formula

Write w(n,k) for the triangle at A193821. The triangle at A193822 is then given by w(n,n-k).

A193823 Triangular array: the fusion of polynomial sequences P and Q given by p(n,x)=(2x+1)^n and q(n,x)=x^n+x^(n-1)+...+x+1.

Original entry on oeis.org

1, 1, 1, 1, 3, 3, 1, 5, 9, 9, 1, 7, 19, 27, 27, 1, 9, 33, 65, 81, 81, 1, 11, 51, 131, 211, 243, 243, 1, 13, 73, 233, 473, 665, 729, 729, 1, 15, 99, 379, 939, 1611, 2059, 2187, 2187, 1, 17, 129, 577, 1697, 3489, 5281, 6305, 6561, 6561, 1, 19, 163, 835, 2851
Offset: 0

Views

Author

Clark Kimberling, Aug 06 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.

Examples

			First six rows:
1
1....1
1....3....3
1....5....9....9
1....7....19...27...27
1....9....33...65...81...81
		

Crossrefs

Programs

  • Mathematica
    z = 10; a = 2; b = 1;
    p[n_, x_] := (a*x + b)^n
    q[0, x_] := 1
    q[n_, x_] := x*q[n - 1, x] + 1; q[n_, 0] := q[n, x] /. x -> 0;
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]   (* A193823 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193824 *)

Formula

From Peter Bala, Jul 16 2013: (Start)
T(n,k) = sum {i = 0..k} binomial(n-1,k-i)*2^(k-i) for 0 <= k <= n.
O.g.f.: (1 - 2*x*t)^2/( (1 - 3*x*t)*(1 - (2*x + 1)*t) ) = 1 + (1 + x)*t + (1 + 3*x + 3*x^2)*t^2 + .... Cf. A193860.
For n >= 1, the n-th row polynomial R(n,x) = 1/(x-1)*( 3^(n-1)*x^(n+1) - (2*x + 1)^(n-1) ). (End)

A193908 Triangular array: the fusion of (p(n,x)) by (q(n,x)), where p(n,x)=sum{F(k+2)*x^(n-k) : 0<=k<=n}, where F=A000045 (Fibonacci numbers), and q(n,x)=2x*q(n-1,x)+1 with q(0,x)=1.

Original entry on oeis.org

1, 2, 1, 8, 6, 3, 24, 20, 12, 6, 80, 64, 40, 22, 11, 256, 208, 128, 72, 38, 19, 832, 672, 416, 232, 124, 64, 32, 2688, 2176, 1344, 752, 400, 208, 106, 53, 8704, 7040, 4352, 2432, 1296, 672, 344, 174, 87, 28160, 22784, 14080, 7872, 4192, 2176, 1112, 564
Offset: 0

Views

Author

Clark Kimberling, Aug 09 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.
First five rows of P (triangle of coefficients of polynomials p(n,x)):
1
1...2
1...2...3
1...2...3...5
1...2...3...5...8
First five rows of Q:
1
2...1
4...2..1
8...4...2...1
16..8...4...2...1

Examples

			First six rows:
1
2....1
8....6....3
24...20...12...6
80...64...40...22...11
256..208..128..72...38...19
		

Crossrefs

Programs

  • Mathematica
    z = 12;
    p[n_, x_] := Sum[Fibonacci[k + 2]*x^(n - k), {k, 0, n}];
    q[n_, x_] := 2 x*q[n - 1, x] + 1 ; q[0, x_] := 1;
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]  (* A193908 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193909 *)

A196664 Expansion of g.f. (1-5*x)/(1-16*x).

Original entry on oeis.org

1, 11, 176, 2816, 45056, 720896, 11534336, 184549376, 2952790016, 47244640256, 755914244096, 12094627905536, 193514046488576, 3096224743817216, 49539595901075456, 792633534417207296, 12682136550675316736, 202914184810805067776, 3246626956972881084416
Offset: 0

Views

Author

Philippe Deléham, Oct 05 2011

Keywords

Crossrefs

Programs

  • Mathematica
    Join[{1},Table[11 16^(n-1),{n,20}]] (* Harvey P. Dale, Oct 20 2011 *)

Formula

a(0) = 1, a(n) = 11*16^(n-1) for n>0.
a(n) = Sum_{k=0..n} A193722(n,k)*5^k.
From Elmo R. Oliveira, Mar 18 2025: (Start)
E.g.f.: (11*exp(16*x) + 5)/16.
a(n) = 16*a(n-1). (End)

A202670 Symmetric matrix based on A000290 (the squares), by antidiagonals.

Original entry on oeis.org

1, 4, 4, 9, 17, 9, 16, 40, 40, 16, 25, 73, 98, 73, 25, 36, 116, 184, 184, 116, 36, 49, 169, 298, 354, 298, 169, 49, 64, 232, 440, 584, 584, 440, 232, 64, 81, 305, 610, 874, 979, 874, 610, 305, 81, 100, 388, 808, 1224, 1484, 1484, 1224, 808, 388, 100, 121
Offset: 1

Views

Author

Clark Kimberling, Dec 22 2011

Keywords

Comments

Let s=(1,4,9,16,...) and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A202670 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A202671 for characteristic polynomials of principal submatrices of M.
...
row 1 (1,4,9,16,...) A000290
row 2 (4,17,40,73,...) A145995
diagonal (1,17,98,354,...) A000538
antidiagonal sums (1,8,35,112,...) A040977
...
The n-th "square border sum" m(n,1)+m(n,2)+...+m(n,n)+m(n-1,n)+m(n-2,n)+...+m(1,n) is a squared square pyramidal number: [n*(n+1)*(2*n+1)/6]^2; see A000330.

Examples

			Northwest corner:
1.....4......9....16....25
4....17.....40....73...116
9....40.....98...184...298
16...73....184...354...584
25...116...298...584...979
		

Crossrefs

Programs

  • Mathematica
    U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[ Table[k^2, {k, 1, 12}]];
    L = Transpose[U]; M = L.U; TableForm[M]
    m[i_, j_] := M[[i]][[j]];
    Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]

A202876 Symmetric matrix based on A000071, by antidiagonals.

Original entry on oeis.org

1, 2, 2, 4, 5, 4, 7, 10, 10, 7, 12, 18, 21, 18, 12, 20, 31, 38, 38, 31, 20, 33, 52, 66, 70, 66, 52, 33, 54, 86, 111, 122, 122, 111, 86, 54, 88, 141, 184, 206, 214, 206, 184, 141, 88, 143, 230, 302, 342, 362, 362, 342, 302, 230, 143, 232, 374, 493, 562, 602
Offset: 1

Views

Author

Clark Kimberling, Dec 26 2011

Keywords

Comments

Let s=A000071 (Fibonacci numbers -1), and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A202876 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A202877 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Examples

			Northwest corner:
1....2....4....7....12....20
2....5....10...18...31....52
4....10...21...38...66....111
7....18...38...70...122...206
12...31...66...122..214...362
		

Crossrefs

Programs

  • Mathematica
    s[k_] := -1 + Fibonacci[k + 2];
    U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[s[k], {k, 1, 15}]];
    L = Transpose[U]; M = L.U; TableForm[M]
    m[i_, j_] := M[[i]][[j]];
    Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]
    f[n_] := Sum[m[i, n], {i, 1, n}] + Sum[m[n, j], {j, 1, n - 1}]
    Table[f[n], {n, 1, 12}]
    Table[Sqrt[f[n]], {n, 1, 12}]  (* A001924 *)
    Table[m[1, j], {j, 1, 12}]     (* A000071 *)
    Table[m[j, j], {j, 1, 12}]     (* A202462 *)

A203949 Symmetric matrix based on (1,1,0,1,1,0,1,1,0,...), by antidiagonals.

Original entry on oeis.org

1, 1, 1, 0, 2, 0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 0, 2, 1, 1, 2, 0, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 0, 2, 1, 1, 4, 1, 1, 2, 0, 1, 1, 1, 3, 2, 2, 3, 1, 1, 1, 1, 1, 2, 2, 2, 4, 2, 2, 2, 1, 1, 0, 2, 1, 1, 4, 2, 2, 4, 1, 1, 2, 0, 1, 1, 1, 3, 2, 2, 5, 2, 2, 3, 1, 1, 1, 1, 1, 2, 2, 2, 4, 3, 3
Offset: 1

Views

Author

Clark Kimberling, Jan 08 2012

Keywords

Comments

Let s be the periodic sequence (1,1,0,1,1,0,...) and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A203949 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A203950 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Examples

			Northwest corner:
1 1 0 1 1 0 1 1 0 1
1 2 1 1 2 1 1 2 1 1
0 1 2 1 1 2 1 1 2 1
1 1 1 3 2 1 3 2 1 3
1 2 1 2 4 2 2 4 2 2
0 1 2 1 2 4 2 2 4 2
1 1 1 3 2 2 5 3 2 5
		

Crossrefs

Programs

  • Mathematica
    t = {1, 1, 0}; t1 = Flatten[{t, t, t, t, t, t, t, t, t}];
    s[k_] := t1[[k]];
    U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[
       Table[s[k], {k, 1, 15}]];
    L = Transpose[U]; M = L.U; TableForm[M] (* A203949 *)
    m[i_, j_] := M[[i]][[j]];
    Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]

A203951 Symmetric matrix based on (1,0,0,0,1,0,0,0,...), by antidiagonals.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Jan 08 2012

Keywords

Comments

Let s be the periodic sequence (1,0,0,0,1,0,0,0,...) and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A203951 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A203952 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Examples

			Northwest corner:
1 0 0 0 1 0 0 0 1 0
0 1 0 0 0 1 0 0 0 1
0 0 1 0 0 0 1 0 0 0
0 0 0 1 0 0 0 1 0 0
1 0 0 0 2 0 0 0 2 0
0 1 0 0 0 2 0 0 0 2
0 0 1 0 0 0 2 0 0 0
0 0 0 1 0 0 0 2 0 0
1 0 0 0 2 0 0 0 3 0
		

Crossrefs

Programs

  • Mathematica
    t = {1, 0, 0, 0}; t1 = Flatten[{t, t, t, t, t, t, t, t}];
    f[k_] := t1[[k]];
    U[n_] :=
      NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[
       Table[f[k], {k, 1, n}]];
    L[n_] := Transpose[U[n]];
    p[n_] := CharacteristicPolynomial[L[n].U[n], x];
    c[n_] := CoefficientList[p[n], x]
    TableForm[Flatten[Table[p[n], {n, 1, 10}]]]
    Table[c[n], {n, 1, 12}]
    Flatten[%]  (* A203952 *)

A193724 Triangular array: the fusion of polynomial sequences P and Q given by p(n,x)=(x+2)^n and q(n,x)=(x+1)^n.

Original entry on oeis.org

1, 1, 1, 2, 5, 3, 4, 16, 21, 9, 8, 44, 90, 81, 27, 16, 112, 312, 432, 297, 81, 32, 272, 960, 1800, 1890, 1053, 243, 64, 640, 2736, 6480, 9180, 7776, 3645, 729, 128, 1472, 7392, 21168, 37800, 43092, 30618, 12393, 2187, 256, 3328, 19200, 64512, 139104
Offset: 0

Views

Author

Clark Kimberling, Aug 04 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.
Triangle T(n,k), read by rows, given by [1,1,0,0,0,0,0,0,0,...] DELTA [1,2,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 04 2011

Examples

			First six rows:
   1;
   1,   1;
   2,   5,   3;
   4,  16,  21,   9;
   8,  44,  90,  81,  27;
  16, 112, 312, 432, 297, 81;
		

Crossrefs

Programs

  • Mathematica
    z = 8; a = 1; b = 2; c = 1; d = 1;
    p[n_, x_] := (a*x + b)^n ; q[n_, x_] := (c*x + d)^n
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]] (* A193724 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193725 *)

Formula

T(n,k) = 3*T(n-1,k-1) + 2*T(n-1,k) with T(0,0)=T(1,0)=T(1,1)=1. - Philippe Deléham, Oct 05 2011
G.f.: (-1+x+2*x*y)/(-1+2*x+3*x*y). - R. J. Mathar, Aug 11 2015

A193726 Triangular array: the fusion of polynomial sequences P and Q given by p(n,x)=(x+2)^n and q(n,x)=(x+2)^n.

Original entry on oeis.org

1, 1, 2, 2, 9, 10, 4, 28, 65, 50, 8, 76, 270, 425, 250, 16, 192, 920, 2200, 2625, 1250, 32, 464, 2800, 9000, 16250, 15625, 6250, 64, 1088, 7920, 32000, 77500, 112500, 90625, 31250, 128, 2496, 21280, 103600, 315000, 612500, 743750, 515625, 156250
Offset: 0

Views

Author

Clark Kimberling, Aug 04 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.
Triangle T(n,k), read by rows, given by (1,1,0,0,0,0,0,0,0,...) DELTA (2,3,0,0,0,0,0,0,0,...) where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 05 2011

Examples

			First six rows:
   1;
   1,   2;
   2,   9,  10;
   4,  28,  65,   50;
   8,  76, 270,  425,  250;
  16, 192, 920, 2200, 2625, 1250;
		

Crossrefs

Programs

  • Magma
    function T(n, k) // T = A193726
      if k lt 0 or k gt n then return 0;
      elif n lt 2 then return k+1;
      else return 2*T(n-1, k) + 5*T(n-1, k-1);
      end if;
    end function;
    [T(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Dec 02 2023
    
  • Mathematica
    (* First program *)
    z = 8; a = 1; b = 2; c = 1; d = 2;
    p[n_, x_] := (a*x + b)^n ; q[n_, x_] := (c*x + d)^n
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]  (* A193726 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193727 *)
    (* Second program *)
    T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[n<2, k+1, 2*T[n-1, k] + 5*T[n -1, k-1]]];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Dec 02 2023 *)
  • SageMath
    def T(n, k): # T = A193726
        if (k<0 or k>n): return 0
        elif (n<2): return k+1
        else: return 2*T(n-1, k) + 5*T(n-1, k-1)
    flatten([[T(n, k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Dec 02 2023

Formula

T(n,k) = 5*T(n-1,k-1) + 2*T(n-1,k) with T(0,0)=T(1,0)=1 and T(1,1)=2. - Philippe Deléham, Oct 05 2011
G.f.: (1-x-3*x*y)/(1-2*x-5*x*y). - R. J. Mathar, Aug 11 2015
From G. C. Greubel, Dec 02 2023: (Start)
T(n, 0) = A011782(n).
T(n, n) = A020699(n).
T(n, n-1) = A081040(n-1).
Sum_{k=0..n} T(n, k) = A169634(n-1) + (4/7)*[n=0].
Sum_{k=0..n} (-1)^k * T(n, k) = (-1)^n*A133494(n) = -A141413(n+1).
Sum_{k=0..floor(n/2)} T(n-k, k) = A002532(n) + 2*A002532(n-1) + (3/5)*[n=0].
Sum_{k=0..floor(n/2)} (-1)^k * T(n-k, k) = A045873(n) - 2*A045873(n-1) + (3/5)*[n=0]. (End)
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