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 1-3 of 3 results.

A319861 Triangle read by rows, 0 <= k <= n: T(n,k) is the numerator of the k-th Bernstein basis polynomial of degree n evaluated at the interval midpoint t = 1/2; denominator is A319862.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 1, 3, 1, 1, 1, 5, 5, 5, 5, 1, 1, 3, 15, 5, 15, 3, 1, 1, 7, 21, 35, 35, 21, 7, 1, 1, 1, 7, 7, 35, 7, 7, 1, 1, 1, 9, 9, 21, 63, 63, 21, 9, 9, 1, 1, 5, 45, 15, 105, 63, 105, 15, 45, 5, 1, 1, 11, 55, 165, 165, 231, 231, 165, 165, 55, 11, 1
Offset: 0

Views

Author

Keywords

Comments

In Computer-Aided Geometric Design, the affine combination Sum_{k=0..n} (T(n,k)/A319862(n,k))*P_k is the halfway point for the Bézier curve of degree n defined by the control points P_k, k = 0, 1, ..., n.

Examples

			Triangle begins:
  1;
  1, 1;
  1, 1,  1;
  1, 3,  3,  1;
  1, 1,  3,  1,   1;
  1, 5,  5,  5,   5,  1;
  1, 3, 15,  5,  15,  3,   1;
  1, 7, 21, 35,  35, 21,   7,  1;
  1, 1,  7,  7,  35,  7,   7,  1,  1;
  1, 9,  9, 21,  63, 63,  21,  9,  9, 1;
  1, 5, 45, 15, 105, 63, 105, 15, 45, 5, 1;
  ...
		

Crossrefs

Programs

  • GAP
    Flat(List([0..11],n->List([0..n],k->Binomial(n,k)/Gcd(Binomial(n,k),2^n)))); # Muniru A Asiru, Sep 30 2018
    
  • Maple
    a:=(n,k)->binomial(n,k)/gcd(binomial(n,k),2^n): seq(seq(a(n,k),k=0..n),n=0..11); # Muniru A Asiru, Sep 30 2018
  • Mathematica
    T[n_, k_] = Binomial[n, k]/GCD[Binomial[n, k], 2^n];
    tabl[nn_] = TableForm[Table[T[n, k], {n, 0, nn}, {k, 0, n}]];
  • Maxima
    T(n,k) := binomial(n, k)/gcd(binomial(n, k), 2^n)$
    tabl(nn) := for n:0 thru nn do print(makelist(T(n, k), k, 0, n))$
    
  • Sage
    flatten([[numerator(binomial(n,k)/2^n) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 19 2021

Formula

T(n, k) = numerator of binomial(n,k)/2^n.
T(n, k) = binomial(n,k)/A082907(n,k).
T(n, k)/A319862(n,k) = binomial(n,k)/2^n.
T(n, n-k) = T(n,k).
T(n, 0) = 1.
T(n, 1) = A000265(n) (with offset 0, following Peter Luschny's formula).
T(n, 2) = A069834(n-1), n > 1.
Sum_{k=0..n} 2*k*T(n,k)/A319862(n,k) = n.
Sum_{k=0..n} 2*k^2*T(n,k)/A319862(n,k) = A000217(n).

A320085 Triangle read by rows, 0 <= k <= n: T(n,k) is the numerator of the derivative of the k-th Bernstein basis polynomial of degree n evaluated at the interval midpoint t = 1/2; denominator is A320086.

Original entry on oeis.org

0, -1, 1, -1, 0, 1, -3, -3, 3, 3, -1, -1, 0, 1, 1, -5, -15, -5, 5, 15, 5, -3, -3, -15, 0, 15, 3, 3, -7, -35, -63, -35, 35, 63, 35, 7, -1, -3, -7, -7, 0, 7, 7, 3, 1, -9, -63, -45, -63, -63, 63, 63, 45, 63, 9, -5, -5, -135, -15, -105, 0, 105, 15, 135, 5, 5
Offset: 0

Views

Author

Keywords

Comments

If n = 2*k, then T(n,k) = 0 since the k-th Bernstein basis polynomial of degree n has a single unique local maximum occurring at t = k/n, which coincides with the interval midpoint t = 1/2 (T(0,0) = 0 because the only 0 degree Bernstein basis polynomial is the constant 1).

Examples

			Triangle begins:
   0;
  -1,   1;
  -1,   0,    1;
  -3,  -3,    3,   3;
  -1,  -1,    0,   1,    1;
  -5, -15,   -5,   5,   15,  5;
  -3,  -3,  -15,   0,   15,  3,   3;
  -7, -35,  -63, -35,   35, 63,  35,  7;
  -1,  -3,   -7,  -7,    0,  7,   7,  3,   1;
  -9, -63,  -45, -63,  -63, 63,  63, 45,  63, 9;
  -5,  -5, -135, -15, -105,  0, 105, 15, 135, 5, 5;
  ...
		

Crossrefs

Programs

  • Maple
    T:=proc(n,k) n*(binomial(n-1,k-1)-binomial(n-1,k))/gcd(n*(binomial(n-1,k-1)-binomial(n-1,k)),2^(n-1)); end proc: seq(seq(T(n,k),k=0..n),n=0..11); # Muniru A Asiru, Oct 06 2018
  • Mathematica
    Table[Numerator[n*(Binomial[n-1, k-1] - Binomial[n-1, k])/2^(n-1)], {n, 0, 12}, {k, 0, n}]//Flatten
  • Maxima
    T(n, k) := n*(binomial(n - 1, k - 1) - binomial(n - 1, k))/gcd(n*(binomial(n - 1, k - 1) - binomial(n - 1, k)), 2^(n - 1))$
    tabl(nn) := for n:0 thru nn do print(makelist(T(n, k), k, 0, n))$
    
  • Sage
    def A320085(n,k): return numerator(n*(binomial(n-1, k-1) - binomial(n-1, k))/2^(n-1))
    flatten([[A320085(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 19 2021

Formula

T(n, k) = numerator of 2*A141692(n,k)/A000079(n).
T(n, k) = n*(binomial(n-1, k-1) - binomial(n-1, k))/gcd(n*(binomial(n-1, k-1) - binomial(n-1, k)), 2^(n-1)).
T(n, n-k) = -T(n,k).
T(n, 0) = -n.
T(2*n+1, 1) = -A000466(n).
T(2*n, 1) = -A069834(n-1), n > 1.
T(n, k)/A320086(n,k) = 4*n*(k/n - 1/2)*A319861(n,k)/A319861(n,k).
Sum_{k=0..n} k*T(n,k)/A320086(n,k) = n.
Sum_{k=0..n} k^2*T(n,k)/A320086(n,k) = n^2.
Sum_{k=0..n} k*(k-1)*T(n,k)/A320086(n,k) = n*(n - 1).

A320086 Triangle read by rows, 0 <= k <= n: T(n,k) is the denominator of the derivative of the k-th Bernstein basis polynomial of degree n evaluated at the interval midpoint t = 1/2; numerator is A320085.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 4, 4, 4, 4, 2, 1, 1, 1, 2, 16, 16, 8, 8, 16, 16, 16, 4, 16, 1, 16, 4, 16, 64, 64, 64, 64, 64, 64, 64, 64, 16, 8, 8, 8, 1, 8, 8, 8, 16, 256, 256, 64, 64, 128, 128, 64, 64, 256, 256, 256, 32, 256, 16, 128, 1, 128, 16, 256, 32, 256
Offset: 0

Views

Author

Keywords

Examples

			Triangle begins:
    1;
    1,   1;
    1,   1,   1;
    4,   4,   4,  4;
    2,   1,   1,  1,   2;
   16,  16,   8,  8,  16,  16;
   16,   4,  16,  1,  16,   4,  16;
   64,  64,  64, 64,  64,  64,  64, 64;
   16,   8,   8,  8,   1,   8,   8,  8,  16;
  256, 256,  64, 64, 128, 128,  64, 64, 256, 256;
  256,  32, 256, 16, 128,   1, 128, 16, 256,  32, 256;
  ...
		

Crossrefs

Programs

  • Maple
    T:=proc(n,k) 2^(n-1)/gcd(n*(binomial(n-1,k-1)-binomial(n-1,k)),2^(n-1)); end proc: seq(seq(T(n,k),k=0..n),n=1..11); # Muniru A Asiru, Oct 06 2018
  • Mathematica
    Table[Denominator[n*(Binomial[n-1, k-1] - Binomial[n-1, k])/2^(n-1)], {n, 0, 12}, {k, 0, n}]//Flatten
  • Maxima
    T(n, k) := 2^(n - 1)/gcd(n*(binomial(n - 1, k - 1) - binomial(n - 1, k)), 2^(n - 1))$
    tabl(nn) := for n:0 thru nn do print(makelist(T(n, k), k, 0, n))$
    
  • Sage
    def A320086(n,k): return denominator(n*(binomial(n-1, k-1) - binomial(n-1, k))/2^(n-1))
    flatten([[A320086(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 19 2021

Formula

T(n, k) = denominator of 2*A141692(n,k)/A000079(n).
T(n, k) = 2^(n-1)/gcd(n*(binomial(n-1, k-1) - binomial(n-1, k)), 2^(n-1)).
T(n, n-k) = T(n,k).
T(n, 0) = A084623(n), n > 0.
T(2*n+1, 1) = A000302(n).
Showing 1-3 of 3 results.