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 14 results. Next

A132045 Row sums of triangle A132044.

Original entry on oeis.org

1, 2, 3, 6, 13, 28, 59, 122, 249, 504, 1015, 2038, 4085, 8180, 16371, 32754, 65521, 131056, 262127, 524270, 1048557, 2097132, 4194283, 8388586, 16777193, 33554408, 67108839, 134217702, 268435429, 536870884, 1073741795, 2147483618, 4294967265, 8589934560
Offset: 0

Views

Author

Gary W. Adamson, Aug 08 2007

Keywords

Comments

Apart from initial terms, and with a change of offset, same as A095768. - Jon E. Schoenfield, Jun 15 2017

Examples

			a(4) = 13 = sum of row 4 terms of triangle A132044: (1 + 3 + 5 + 3 + 1).
a(4) = 13 = (1, 4, 6, 4, 1) dot (1, 1, 0, 2, 0) = (1 + 4 + 0 + 8 + 0).
		

Crossrefs

Programs

  • Magma
    [1] cat [2^n -n +1: n in [1..35]]; // G. C. Greubel, Feb 12 2021
  • Mathematica
    Table[2^n -(n-1) -Boole[n==0], {n, 0, 35}] (* G. C. Greubel, Feb 12 2021 *)
  • PARI
    Vec((1-2*x+2*x^3)/((1-x)^2*(1-2*x)) + O(x^100)) \\ Colin Barker, Mar 14 2014
    
  • Sage
    [1]+[2^n -n +1 for n in (1..35)] # G. C. Greubel, Feb 12 2021
    

Formula

Binomial transform of (1, 1, 0, 2, 0, 2, 0, 2, 0, 2, ...).
For n>=1, a(n) = 2^n - n + 1 = A000325(n) + 1. - Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 17 2009. (Corrected by Franklin T. Adams-Watters, Jan 17 2009)
E.g.f.: U(0) - 1, where U(k) = 1 - x/(2^k + 2^k/(x - 1 - x^2*2^(k+1)/(x*2^(k+1) + (k+1)/U(k+1)))). - Sergei N. Gladkovskii, Dec 01 2012
From Colin Barker, Mar 14 2014: (Start)
a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3) for n>3.
G.f.: (1-2*x+2*x^3) / ((1-x)^2*(1-2*x)). (End)

A173075 T(n,k) = binomial(n, k) - 1 + q^(floor(n/2))*binomial(n-2, k-1) for 0 < k < n with T(n,0) = T(n,n) = 1 and q = 1. Triangle read by rows.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 7, 4, 1, 1, 5, 12, 12, 5, 1, 1, 6, 18, 25, 18, 6, 1, 1, 7, 25, 44, 44, 25, 7, 1, 1, 8, 33, 70, 89, 70, 33, 8, 1, 1, 9, 42, 104, 160, 160, 104, 42, 9, 1, 1, 10, 52, 147, 265, 321, 265, 147, 52, 10, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 09 2010

Keywords

Comments

Rows two through six appear in the table on p. 8 of Getzler. Cf. also A167763. - Tom Copeland, Jan 22 2020
The triangle sequences having the form T(n,k,p) = binomial(n, k) + p^n*binomial(n-2, k-1) - 1 have the row sums Sum_{k=0..n} T(n,k,p) = 2^(n-2)*p^n + 2^n - (n-1) - (5/4)*[n=0] -(p/2)*[n=1]. - G. C. Greubel, Feb 12 2021

Examples

			Triangle begins:
  1,
  1,  1;
  1,  2,  1;
  1,  3,  3,   1;
  1,  4,  7,   4,   1;
  1,  5, 12,  12,   5,   1;
  1,  6, 18,  25,  18,   6,   1;
  1,  7, 25,  44,  44,  25,   7,   1;
  1,  8, 33,  70,  89,  70,  33,   8,  1;
  1,  9, 42, 104, 160, 160, 104,  42,  9,  1;
  1, 10, 52, 147, 265, 321, 265, 147, 52, 10, 1;
  ...
Row sums: {1, 2, 4, 8, 17, 36, 75, 154, 313, 632, 1271, ...}.
		

Crossrefs

Cf. A132044 (q=0), this sequence (q=1), A173076 (q=2), A173077 (q=3).
Cf. A132044 (p=0), this sequence (p=1), A173046 (p=2), A173047 (p=3).
Cf. A167763.

Programs

  • Magma
    T:= func< n,k,p | k eq 0 or k eq n select 1 else Binomial(n,k) + p^n*Binomial(n-2,k-1) -1 >;
    [T(n,k,1): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 12 2021
  • Mathematica
    T[n_, m_]:= If[m==0 || m==n, 1, Binomial[n, m] - 1 + Binomial[n-2, m-1]];
    Table[T[n, m], {n, 0, 10}, {m, 0, n}]//Flatten
  • PARI
    T(n,k)={if(k<=0||k>=n, k==0||k==n, binomial(n,k) - 1 + binomial(n-2, k-1))} \\ Andrew Howroyd, Jan 22 2020
    
  • Sage
    def T(n,k,p): return 1 if (k==0 or k==n) else binomial(n,k) + p^n*binomial(n-2,k-1) -1
    flatten([[T(n,k,1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 12 2021
    

Formula

T(n, k) = binomial(n, k) - 1 + binomial(n-2, k-1) for 0 < k < n.
T(n, 0) = T(n, n) = 1.
From G. C. Greubel, Feb 12 2021: (Start)
T(n, k, p) = binomial(n, k) + p^n*binomial(n-2, k-1) - 1 with T(n, 0) = T(n, n) = 1 and p = 1.
Sum_{k=0..n} T(n, k, 1) = 2^(n-2) + 2^n - (n-1) - (5/4)*[n=0] -(1/2)*[n=1]. (End)

A132735 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, 3, 1, 1, 4, 4, 1, 1, 5, 7, 5, 1, 1, 6, 11, 11, 6, 1, 1, 7, 16, 21, 16, 7, 1, 1, 8, 22, 36, 36, 22, 8, 1, 1, 9, 29, 57, 71, 57, 29, 9, 1, 1, 10, 37, 85, 127, 127, 85, 37, 10, 1, 1, 11, 46, 121, 211, 253, 211, 121, 46, 11, 1, 1, 12, 56, 166, 331, 463, 463, 331, 166, 56, 12, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 26 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  1, 3,  1;
  1, 4,  4,  1;
  1, 5,  7,  5,  1;
  1, 6, 11, 11,  6, 1;
  1, 7, 16, 21, 16, 7, 1;
  ...
		

Crossrefs

Sequences of the form binomial(n, k) + q: A132823 (q=-2), A132044 (q=-1), A007318 (q=0), this sequence (q=1), A173740 (q=2), A173741 (q=4), A173742 (q=6).

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else Binomial(n,k) + 1 >;
    [T(n,k): k in [0..n], n in [0..12]]; // _G. C. Greubel, Feb 14 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 (* G. C. Greubel, Feb 14 2021 *)
  • Sage
    def T(n, k): return 1 if (k==0 or k==n) else binomial(n, k) + 1
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 14 2021
    

Formula

T(n, k) = A007318(n,k) + 1 - A103451(n,k), an infinite lower triangular matrix.
T(n,0) = T(n,n) = 1; T(n,k) = C(n,k) + 1 otherwise. - Franklin T. Adams-Watters, Jul 06 2009
Sum_{k=0..n} T(n, k) = 2^n + n - 1 + [n=0] = A132736(n). - G. C. Greubel, Feb 14 2021

Extensions

Corrected and extended by Franklin T. Adams-Watters, Jul 06 2009

A173740 Triangle T(n,k) = binomial(n,k) + 2 for 1 <= k <= n - 1, n >= 2, and T(n,0) = T(n,n) = 1 for n >= 0, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 5, 5, 1, 1, 6, 8, 6, 1, 1, 7, 12, 12, 7, 1, 1, 8, 17, 22, 17, 8, 1, 1, 9, 23, 37, 37, 23, 9, 1, 1, 10, 30, 58, 72, 58, 30, 10, 1, 1, 11, 38, 86, 128, 128, 86, 38, 11, 1, 1, 12, 47, 122, 212, 254, 212, 122, 47, 12, 1, 1, 13, 57, 167, 332, 464, 464, 332, 167, 57, 13, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 23 2010

Keywords

Comments

For n >= 1, row n sums to A131520(n).

Examples

			Triangle begins:
  1;
  1,  1;
  1,  4,  1;
  1,  5,  5,   1;
  1,  6,  8,   6,   1;
  1,  7, 12,  12,   7,   1;
  1,  8, 17,  22,  17,   8,   1;
  1,  9, 23,  37,  37,  23,   9,   1;
  1, 10, 30,  58,  72,  58,  30,  10,  1;
  1, 11, 38,  86, 128, 128,  86,  38, 11,  1;
  1, 12, 47, 122, 212, 254, 212, 122, 47, 12, 1;
  ...
		

Crossrefs

Sequences of the form binomial(n, k) + q: A132823 (q=-2), A132044 (q=-1), A007318 (q=0), A132735 (q=1), this sequence (q=2), A173741 (q=4), A173742 (q=6).

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else Binomial(n,k) + 2 >;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 13 2021
  • Mathematica
    T[n_, m_] = Binomial[n, m] + 2*If[m*(n - m) > 0, 1, 0];
    Flatten[Table[T[n, m], {n, 0, 10}, {m, 0, n}]]
  • Maxima
    T(n,k) := if k = 0 or k = n then 1 else binomial(n, k) + 2$
    create_list(T(n, k), n, 0, 12, k, 0, n); /* Franck Maminirina Ramaharo, Dec 08 2018 */
    
  • Sage
    def T(n, k): return 1 if (k==0 or k==n) else binomial(n, k) + 2
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 13 2021
    

Formula

From Franck Maminirina Ramaharo, Dec 08 2018:(Start)
T(n,k) = A007318(n,k) + 2*(1 - A103451(n,k)).
T(n,k) = 3*A007318(n,k) - 2*A132044(n,k).
n-th row polynomial is 1 - (-1)^(2^n) + (1 + x)^n + 2*(x - x^n)/(1 - x).
G.f.: (1 - (1 + x)*y + 3*x*y^2 - 2*(x + x^2)*y^3)/((1 - y)*(1 - x*y)*(1 - y - x*y)).
E.g.f.: (2 - 2*x + 2*x*exp(y) - 2*exp(x*y) + (1 - x)*exp((1 + x)*y))/(1 - x). (End)
Sum_{k=0..n} T(n, k) = 2^n + 2*(n - 1 + [n=0]) = 2*A100314(n). - G. C. Greubel, Feb 13 2021

Extensions

Edited and name clarified by Franck Maminirina Ramaharo, Dec 08 2018

A132731 Triangle T(n,k) = 2 * binomial(n,k) - 2 with T(n,0) = T(n,n) = 1, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 6, 10, 6, 1, 1, 8, 18, 18, 8, 1, 1, 10, 28, 38, 28, 10, 1, 1, 12, 40, 68, 68, 40, 12, 1, 1, 14, 54, 110, 138, 110, 54, 14, 1, 1, 16, 70, 166, 250, 250, 166, 70, 16, 1, 1, 18, 88, 238, 418, 502, 418, 238, 88, 18, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 26 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  1,  1;
  1,  2,  1;
  1,  4,  4,  1;
  1,  6, 10,  6,  1;
  1,  8, 18, 18,  8,  1;
  1, 10, 28, 38, 28, 10,  1;
  1, 12, 40, 68, 68, 40, 12, 1;
  ...
		

Crossrefs

Cf. A000012, A007318, A103451, A132044, A132732 (row sums).

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else 2*Binomial(n,k) - 2 >;
    [T(n,k): k in [0..n], n in [0..12]]; // _G. C. Greubel, Feb 14 2021
  • Mathematica
    T[n_, k_]:= If[k==0 || k==n, 1, 2*Binomial[n, k] - 2];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 14 2021 *)
  • PARI
    t(n,k) =  2*binomial(n, k) + ((k==0) || (k==n)) - 2*(k<=n); \\ Michel Marcus, Feb 12 2014
    
  • Sage
    def T(n, k): return 1 if (k==0 or k==n) else 2*binomial(n, k) - 2
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 14 2021
    

Formula

T(n, k) = 2*A007318 + A103451 - 2*A000012, an infinite lower triangular matrix.
From G. C. Greubel, Feb 14 2021: (Start)
T(n, k) = 2*binomial(n, k) - 2 with T(n, 0) = T(n, n) = 1.
T(n, k) = 2*A132044(n, k) with T(n, 0) = T(n, n) = 1.
Sum_{k=0..n} T(n, k) = 2^(n+1) - 2*n - [n=0] = A132732(n). (End)

Extensions

Corrected by Jeremy Gardiner, Feb 02 2014
More terms from Michel Marcus, Feb 12 2014

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

A173741 T(n,k) = binomial(n,k) + 4 for 1 <= k <= n - 1, n >= 2, and T(n,0) = T(n,n) = 1 for n >= 0, triangle read by rows.

Original entry on oeis.org

1, 1, 1, 1, 6, 1, 1, 7, 7, 1, 1, 8, 10, 8, 1, 1, 9, 14, 14, 9, 1, 1, 10, 19, 24, 19, 10, 1, 1, 11, 25, 39, 39, 25, 11, 1, 1, 12, 32, 60, 74, 60, 32, 12, 1, 1, 13, 40, 88, 130, 130, 88, 40, 13, 1, 1, 14, 49, 124, 214, 256, 214, 124, 49, 14, 1, 1, 15, 59, 169, 334, 466, 466, 334, 169, 59, 15, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 23 2010

Keywords

Comments

For n >= 1, row n sums to 2*A100314(n).

Examples

			Triangle begins:
  1;
  1,  1;
  1,  6,  1;
  1,  7,  7,   1;
  1,  8, 10,   8,   1;
  1,  9, 14,  14,   9,   1;
  1, 10, 19,  24,  19,  10,   1;
  1, 11, 25,  39,  39,  25,  11,   1;
  1, 12, 32,  60,  74,  60,  32,  12,  1;
  1, 13, 40,  88, 130, 130,  88,  40, 13,  1;
  1, 14, 49, 124, 214, 256, 214, 124, 49, 14, 1;
  ...
		

Crossrefs

Sequences of the form binomial(n, k) + q: A132823 (q=-2), A132044 (q=-1), A007318 (q=0), A132735 (q=1), A173740 (q=2), this sequence (q=4), A173742 (q=6).

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else Binomial(n,k) + 4 >;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 13 2021
  • Mathematica
    T[n_, m_] = Binomial[n, m] + 4*If[m*(n - m) > 0, 1, 0];
    Flatten[Table[T[n, m], {n, 0, 10}, {m, 0, n}]]
  • Maxima
    T(n,k) := if k = 0 or k = n then 1 else binomial(n, k) + 4$
    create_list(T(n, k), n, 0, 12, k, 0, n); /* Franck Maminirina Ramaharo, Dec 09 2018 */
    
  • Sage
    def T(n, k): return 1 if (k==0 or k==n) else binomial(n, k) + 4
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 13 2021
    

Formula

From Franck Maminirina Ramaharo, Dec 09 2018:(Start)
T(n,k) = A007318(n,k) + 2*(1 - A103451(n,k)).
T(n,k) = 5*A007318(n,k) - 4*A132044(n,k).
n-th row polynomial is 2*(1 - (-1)^(2^n)) + (1 + x)^n + 4*(x - x^n)/(1 - x).
G.f.: (1 - (1 + x)*y + 5*x*y^2 - 4*(x + x^2)*y^3)/((1 - y)*(1 - x*y)*(1 - y - x*y)).
E.g.f.: (4 - 4*x + 4*x*exp(y) - 4*exp(x*y) + (1 - x)*exp((1 + x)*y))/(1 - x). (End)
Sum_{k=0..n} T(n, k) = 2^n + 4*(n - 1 + [n=0]) = 2*A100314(n). - G. C. Greubel, Feb 13 2021

Extensions

Edited and name clarified by Franck Maminirina Ramaharo, Dec 09 2018

A173742 Triangle T(n,k) = binomial(n,k) + 6 with T(n,0) = T(n,n) = 1 for n >= 0, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 8, 1, 1, 9, 9, 1, 1, 10, 12, 10, 1, 1, 11, 16, 16, 11, 1, 1, 12, 21, 26, 21, 12, 1, 1, 13, 27, 41, 41, 27, 13, 1, 1, 14, 34, 62, 76, 62, 34, 14, 1, 1, 15, 42, 90, 132, 132, 90, 42, 15, 1, 1, 16, 51, 126, 216, 258, 216, 126, 51, 16, 1, 1, 17, 61, 171, 336, 468, 468, 336, 171, 61, 17, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 23 2010

Keywords

Comments

For n >= 1, row n sums to A131520(n) + A008586(n).

Examples

			Triangle begins:
  1;
  1,  1;
  1,  8,  1;
  1,  9,  9,   1;
  1, 10, 12,  10,   1;
  1, 11, 16,  16,  11,   1;
  1, 12, 21,  26,  21,  12,   1;
  1, 13, 27,  41,  41,  27,  13,   1;
  1, 14, 34,  62,  76,  62,  34,  14,  1;
  1, 15, 42,  90, 132, 132,  90,  42, 15,  1;
  1, 16, 51, 126, 216, 258, 216, 126, 51, 16, 1;
  ...
		

Crossrefs

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else Binomial(n,k) +6 >;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 13 2021
  • Mathematica
    T[n_, m_] = Binomial[n, m] + 6*If[m*(n - m) > 0, 1, 0];
    Flatten[Table[T[n, m], {n, 0, 10}, {m, 0, n}]]
  • Maxima
    T(n,k) := if k = 0 or k = n then 1 else binomial(n, k) + 6$
    create_list(T(n, k), n, 0, 12, k, 0, n); /* Franck Maminirina Ramaharo, Dec 09 2018 */
    
  • Sage
    def T(n, k): return 1 if (k==0 or k==n) else binomial(n, k) + 6
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 13 2021
    

Formula

From Franck Maminirina Ramaharo, Dec 09 2018: (Start)
T(n,k) = A007318(n,k) + 6*(1 - A103451(n,k)).
T(n,k) = 7*A007318(n,k) - 6*A132044(n,k).
n-th row polynomial is 3*(1 - (-1)^(2^n)) + (1 + x)^n + 6*(x - x^n)/(1 - x).
G.f.: (1 - (1 + x)*y + 7*x*y^2 - 6*(x + x^2)*y^3)/((1 - y)*(1 - x*y)*(1 - y - x*y)).
E.g.f.: (6 - 6*x + 6*x*exp(y) - 6*exp(x*y) + (1 - x)*exp((1 + x)*y))/(1 - x). (End)
Sum_{k=0..n} T(n, k) = 2^n + 6*n - 6 + 6*[n=0]. - G. C. Greubel, Feb 13 2021

Extensions

Edited and name clarified by Franck Maminirina Ramaharo, Dec 09 2018

A132729 Triangle T(n, k) = 2*binomial(n, k) - 3 with T(n, 0) = T(n, n) = 1, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 5, 9, 5, 1, 1, 7, 17, 17, 7, 1, 1, 9, 27, 37, 27, 9, 1, 1, 11, 39, 67, 67, 39, 11, 1, 1, 13, 53, 109, 137, 109, 53, 13, 1, 1, 15, 69, 165, 249, 249, 165, 69, 15, 1, 1, 17, 87, 237, 417, 501, 417, 237, 87, 17, 1, 1, 19, 107, 327, 657, 921, 921, 657, 327, 107, 19, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 26 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  1,  1;
  1,  1,  1;
  1,  3,  3,  1;
  1,  5,  9,  5,  1;
  1,  7, 17, 17,  7,  1;
  1,  9, 27, 37, 26,  9,  1;
  1, 11, 39, 67, 67, 39, 11, 1;
		

Crossrefs

Programs

  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else 2*Binomial(n,k) - 3 >;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 13 2021
  • Mathematica
    T[n_, k_]:= If[k==0 || k==n, 1, 2*Binomial[n, k] - 3];
    Table[T[n, k], {n, 0, 10}, {k, 0, n}]//Flatten (* G. C. Greubel, Feb 13 2021 *)
  • Sage
    def T(n,k): return 1 if (k==0 or k==n) else 2*binomial(n,k) - 3
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 13 2021
    

Formula

T(n, k) = 2*A132044(n, k) - 1.
From G. C. Greubel, Feb 13 2021: (Start)
T(n, k) = 2*binomial(n, k) - 3 with T(n, 0) = T(n, n) = 1.
Sum_{k=0..n} T(n, k) = 2^(n+1) - 3*n + 1 - 2*[n=0] = A132730(n). (End)

Extensions

More terms added by G. C. Greubel, Feb 13 2021
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