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 1-6 of 6 results.

A132044 Triangle T(n,k) = binomial(n, k) - 1 with T(n,0) = T(n,n) = 1, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 5, 3, 1, 1, 4, 9, 9, 4, 1, 1, 5, 14, 19, 14, 5, 1, 1, 6, 20, 34, 34, 20, 6, 1, 1, 7, 27, 55, 69, 55, 27, 7, 1, 1, 8, 35, 83, 125, 125, 83, 35, 8, 1, 1, 9, 44, 119, 209, 251, 209, 119, 44, 9, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 08 2007

Keywords

Comments

Row sums = A132045: (1, 2, 3, 6, 13, 28, 59, ...).
The triangle sequences having the form T(n,k,q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 have the row sums Sum_{k=0..n} T(n,k,q) = 2^(n-2)*q^n + 2^n - (n-1) - (5/4)*[n=0] -(q/2)*[n=1]. - G. C. Greubel, Feb 12 2021

Examples

			First few rows of the triangle:
  1;
  1, 1;
  1, 1,  1;
  1, 2,  2,  1;
  1, 3,  5,  3,  1;
  1, 4,  9,  9,  4,  1;
  1, 5, 14, 19, 14,  5,  1;
  1, 6, 20, 34, 34, 20,  6, 1;
  1, 7, 27, 55, 69, 55, 27, 7, 1;
		

Crossrefs

Cf. this sequence (q=0), A173075 (q=1), A173046 (q=2), A173047 (q=3).

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) + q^n*Binomial(n-2,k-1) -1 >;
    [T(n,k,0): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 12 2021
  • Mathematica
    T[n_, k_]:= If[k==0 || k==n, 1, Binomial[n, k] - 1];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* Roger L. Bagula, Feb 08 2010 *)
  • Sage
    def T(n,k,q): return 1 if (k==0 or k==n) else binomial(n,k) + q^n*binomial(n-2,k-1) -1
    flatten([[T(n,k,0) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 12 2021
    

Formula

T(n, k) = A007318(n,k) + A103451(n,k) - A000012(n,k), an infinite lower triangular matrix.
T(n, k) = binomial(n, k) - 1, with T(n,0) = T(n,n) = 1. - Roger L. Bagula, Feb 08 2010
From G. C. Greubel, Feb 12 2021: (Start)
T(n, k, q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and q = 0.
Sum_{k=0..n} T(n, k, 0) = 2^n - (n-1) - [n=0]. (End)

A167763 Pendular triangle (p=0), read by rows, where row n is formed from row n-1 by the recurrence: if n > 2k, T(n,k) = T(n,n-k) + T(n-1,k), otherwise T(n,k) = T(n,n-1-k) + p*T(n-1,k), for n >= k <= 0, with T(n,0) = 1 and T(n,n) = 0^n.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 1, 0, 1, 4, 7, 4, 1, 0, 1, 5, 12, 12, 5, 1, 0, 1, 6, 18, 30, 18, 6, 1, 0, 1, 7, 25, 55, 55, 25, 7, 1, 0, 1, 8, 33, 88, 143, 88, 33, 8, 1, 0, 1, 9, 42, 130, 273, 273, 130, 42, 9, 1, 0, 1, 10, 52, 182, 455, 728, 455, 182, 52, 10, 1, 0
Offset: 0

Views

Author

Philippe Deléham, Nov 11 2009

Keywords

Comments

See A118340 for definition of pendular triangles and pendular sums.
The last five rows in the example section appear in the table on p. 8 of Getzler. Cf. also A173075. - Tom Copeland, Jan 22 2020

Examples

			Triangle begins:
  1;
  1,  0;
  1,  1,  0;
  1,  2,  1,  0;
  1,  3,  3,  1,  0;
  1,  4,  7,  4,  1,  0;
  1,  5, 12, 12,  5,  1,  0; ...
		

Crossrefs

Cf. this sequence (p=0), A118340 (p=1), A118345 (p=2), A118350 (p=3).

Programs

  • Magma
    function T(n,k,p)
      if k lt 0 or n lt k then return 0;
      elif k eq 0 then return 1;
      elif k eq n then return 0;
      elif n gt 2*k then return T(n,n-k,p) + T(n-1,k,p);
      else return T(n,n-k-1,p) + p*T(n-1,k,p);
      end if;
      return T;
    end function;
    [T(n,k,0): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 17 2021
  • Mathematica
    T[n_, k_, p_]:= T[n,k,p] = If[nG. C. Greubel, Feb 17 2021 *)
  • PARI
    {T(n,k)=if(k==0,1,if(n==k,0,if(n>2*k,binomial(n+k+1,k)*(n-2*k+1)/(n+k+1),T(n,n-1-k))))} \\ Paul D. Hanna, Nov 12 2009
    
  • Sage
    @CachedFunction
    def T(n, k, p):
        if (k<0 or n2*k): return T(n,n-k,p) + T(n-1,k,p)
        else: return T(n, n-k-1, p) + p*T(n-1, k, p)
    flatten([[T(n, k, 0) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 17 2021
    

Formula

T(2n+m) = [A001764^(m+1)](n), i.e., the m-th lower semi-diagonal forms the self-convolution (m+1)-power of A001764.
If n > 2k, T(n,k) = binomial(n+k+1,k)*(n-2k+1)/(n+k+1), else T(n,k) = T(n,n-1-k), with conditions: T(n,0)=1 for n>=0 and T(n,n)=0 for n > 0. - Paul D. Hanna, Nov 12 2009
Sum_{k=0..n} T(n, k, p=0) = A093951(n). - G. C. Greubel, Feb 17 2021

A173046 Triangle T(n, k, q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and q = 2, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 10, 10, 1, 1, 19, 37, 19, 1, 1, 36, 105, 105, 36, 1, 1, 69, 270, 403, 270, 69, 1, 1, 134, 660, 1314, 1314, 660, 134, 1, 1, 263, 1563, 3895, 5189, 3895, 1563, 263, 1, 1, 520, 3619, 10835, 18045, 18045, 10835, 3619, 520, 1, 1, 1033, 8236, 28791, 57553, 71931, 57553, 28791, 8236, 1033, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 08 2010

Keywords

Comments

The triangle sequences having the form T(n,k,q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 have the row sums Sum_{k=0..n} T(n,k,q) = 2^(n-2)*q^n + 2^n - (n-1) - (5/4)*[n=0] -(q/2)*[n=1]. - G. C. Greubel, Feb 16 2021

Examples

			Triangle begins as:
  1;
  1,    1;
  1,    5,    1;
  1,   10,   10,     1;
  1,   19,   37,    19,     1;
  1,   36,  105,   105,    36,     1;
  1,   69,  270,   403,   270,    69,     1;
  1,  134,  660,  1314,  1314,   660,   134,     1;
  1,  263, 1563,  3895,  5189,  3895,  1563,   263,    1;
  1,  520, 3619, 10835, 18045, 18045, 10835,  3619,  520,    1;
  1, 1033, 8236, 28791, 57553, 71931, 57553, 28791, 8236, 1033, 1;
		

Crossrefs

Cf. A132044 (q=0), A173075 (q=1), this sequence (q=2), A173047 (q=3).

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) + q^n*Binomial(n-2,k-1) -1 >;
    [T(n,k,2): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 16 2021
  • Mathematica
    T[n_, m_, q_]:= If[k==0 || k==n, 1, Binomial[n, k] +(q^n)*Binomial[n-2, k-1] -1];
    Table[T[n,k,2], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Feb 16 2021 *)
  • Sage
    def T(n,k,q): return 1 if (k==0 or k==n) else binomial(n,k) + q^n*binomial(n-2,k-1) -1
    flatten([[T(n,k,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 16 2021
    

Formula

T(n, k, q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and q = 2.
Sum_{k=0..n} T(n, k, 2) = 4^(n-1) + 2^n - (n-1) - (5/4)*[n=0] = A000302(n-1) + A132045(n) - (5/4)*[n=0]. - [n=1]. - G. C. Greubel, Feb 16 2021

Extensions

Edited by G. C. Greubel, Feb 16 2021

A173047 Triangle T(n, k, q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and q = 3, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 10, 1, 1, 29, 29, 1, 1, 84, 167, 84, 1, 1, 247, 738, 738, 247, 1, 1, 734, 2930, 4393, 2930, 734, 1, 1, 2193, 10955, 21904, 21904, 10955, 2193, 1, 1, 6568, 39393, 98470, 131289, 98470, 39393, 6568, 1, 1, 19691, 137816, 413426, 689030, 689030, 413426, 137816, 19691, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 08 2010

Keywords

Comments

The triangle sequences having the form T(n,k,q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 have the row sums Sum_{k=0..n} T(n,k,q) = 2^(n-2)*q^n + 2^n - (n-1) - (5/4)*[n=0] -(q/2)*[n=1]. - G. C. Greubel, Feb 16 2021

Examples

			Ttiangle begins as:
  1;
  1,     1;
  1,    10,      1;
  1,    29,     29,      1;
  1,    84,    167,     84,      1;
  1,   247,    738,    738,    247,      1;
  1,   734,   2930,   4393,   2930,    734,      1;
  1,  2193,  10955,  21904,  21904,  10955,   2193,      1;
  1,  6568,  39393,  98470, 131289,  98470,  39393,   6568,     1;
  1, 19691, 137816, 413426, 689030, 689030, 413426, 137816, 19691, 1;
		

Crossrefs

Cf. A132044 (q=0), A173075 (q=1), A173046 (q=2), this sequence (q=3).

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) + q^n*Binomial(n-2,k-1) -1 >;
    [T(n,k,3): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 16 2021
  • Mathematica
    T[n_, k_, q_]:= If[k==0 || k==n, 1, Binomial[n, k] +(q^n)*Binomial[n-2, k-1] -1];
    Table[T[n,k,3], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Feb 16 2021 *)
  • Sage
    def T(n,k,q): return 1 if (k==0 or k==n) else binomial(n,k) + q^n*binomial(n-2,k-1) -1
    flatten([[T(n,k,3) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 16 2021
    

Formula

T(n, k, q) = binomial(n, k) + q^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and q = 3.
Sum_{k=0..n} T(n, k, 3) = (1/4)*(6^n + 2^(n+2) - 4*(n-1) - 5*[n=0] - 6*[n=1]). - G. C. Greubel, Feb 16 2021

Extensions

Edited by G. C. Greubel, Feb 16 2021

A173076 Triangle T(n, k, q) = binomial(n, k) - 1 + q^(floor(n/2))*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 2, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 4, 4, 1, 1, 7, 13, 7, 1, 1, 8, 21, 21, 8, 1, 1, 13, 46, 67, 46, 13, 1, 1, 14, 60, 114, 114, 60, 14, 1, 1, 23, 123, 295, 389, 295, 123, 23, 1, 1, 24, 147, 419, 685, 685, 419, 147, 24, 1, 1, 41, 300, 1015, 2001, 2491, 2001, 1015, 300, 41, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 09 2010

Keywords

Examples

			Triangle begins as:
  1;
  1,  1;
  1,  3,   1;
  1,  4,   4,    1;
  1,  7,  13,    7,    1;
  1,  8,  21,   21,    8,    1;
  1, 13,  46,   67,   46,   13,    1;
  1, 14,  60,  114,  114,   60,   14,    1;
  1, 23, 123,  295,  389,  295,  123,   23,   1;
  1, 24, 147,  419,  685,  685,  419,  147,  24,  1;
  1, 41, 300, 1015, 2001, 2491, 2001, 1015, 300, 41, 1;
		

Crossrefs

Cf. A132044 (q=0), A173075 (q=1), this sequence (q=2), A173077 (q=3).

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) + q^(Floor(n/2))*Binomial(n-2,k-1) -1 >;
    [T(n,k,2): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 09 2021
    
  • Mathematica
    T[n_, k_, q_]:= If[k==0 || k==n, 1, Binomial[n, k] - 1 + q^(Floor[n/2])*Binomial[n-2, k-1]];
    Table[T[n, k, 2], {n,0,10}, {k,0,n}]//Flatten
  • Sage
    def T(n,k,q): return 1 if (k==0 or k==n) else binomial(n,k) + q^(n//2)*binomial(n-2,k-1) -1
    flatten([[T(n,k,1) for k in (0..n)] for n in (0..12)])

Formula

T(n, k, q) = binomial(n, k) - 1 + q^floor(n/2)*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 2.

Extensions

Edited by G. C. Greubel, Jul 09 2021

A173077 Triangle T(n, k, q) = binomial(n, k) - 1 + q^floor(n/2)*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 3, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 5, 5, 1, 1, 12, 23, 12, 1, 1, 13, 36, 36, 13, 1, 1, 32, 122, 181, 122, 32, 1, 1, 33, 155, 304, 304, 155, 33, 1, 1, 88, 513, 1270, 1689, 1270, 513, 88, 1, 1, 89, 602, 1784, 2960, 2960, 1784, 602, 89, 1, 1, 252, 1988, 6923, 13817, 17261, 13817, 6923, 1988, 252, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 09 2010

Keywords

Examples

			Triangle starts:
  1;
  1,   1;
  1,   4,    1;
  1,   5,    5,    1;
  1,  12,   23,   12,     1;
  1,  13,   36,   36,    13,     1;
  1,  32,  122,  181,   122,    32,     1;
  1,  33,  155,  304,   304,   155,    33,    1;
  1,  88,  513, 1270,  1689,  1270,   513,   88,    1;
  1,  89,  602, 1784,  2960,  2960,  1784,  602,   89,   1;
  1, 252, 1988, 6923, 13817, 17261, 13817, 6923, 1988, 252, 1;
  ...
Row sums: 1, 2, 6, 12, 49, 100, 491, 986, 5433, 10872, 63223, ...
		

Crossrefs

Cf. A132044 (q=0), A173075 (q=1), A173076 (q=2), this sequence (q=3).

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) + q^(Floor(n/2))*Binomial(n-2,k-1) -1 >;
    [T(n,k,3): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 09 2021
    
  • Mathematica
    T[n_, k_]:= If[k==0 || k==n, 1, Binomial[n, k] - 1 + 3^Floor[n/2] Binomial[n-2, k- 1]];
    Table[T[n, k], {n,0,10}, {k,0,n}]//Flatten
  • Sage
    def T(n,k,q): return 1 if (k==0 or k==n) else binomial(n,k) + q^(n//2)*binomial(n-2,k-1) -1
    flatten([[T(n,k,3) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 09 2021

Formula

T(n, k, q) = binomial(n, k) - 1 + q^floor(n/2)*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 3.
Showing 1-6 of 6 results.