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 1-2 of 2 results.

A156645 Triangle T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 2, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 36, 1, 1, 1225, 1225, 1, 1, 41616, 1416100, 41616, 1, 1, 1413721, 1634261476, 1634261476, 1413721, 1, 1, 48024900, 1885939157025, 64069586905104, 1885939157025, 48024900, 1, 1, 1631432881, 2176372249076025, 2511659716192658889, 2511659716192658889, 2176372249076025, 1631432881, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 12 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,        1;
  1,       36,             1;
  1,     1225,          1225,              1;
  1,    41616,       1416100,          41616,             1;
  1,  1413721,    1634261476,     1634261476,       1413721,        1;
  1, 48024900, 1885939157025, 64069586905104, 1885939157025, 48024900, 1;
		

Crossrefs

Cf. A007318 (m=0), A173585 (m=1), this sequence (m=2), A156646 (m=10).

Programs

  • Magma
    b:= func< n, k | n eq 0 select 1 else k eq 0 select Factorial(n) else (&*[1 - Evaluate(ChebyshevT(j), k+1)^2 : j in [1..n]]) >;
    T:= func< n,k,m | b(n,m)/(b(k,m)*b(n-k,m)) >;
    [T(n,k,2): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 03 2021
    
  • Mathematica
    (* First program *)
    b[n_, k_]:= b[n,k]= If[k==0, n!, Product[1 -ChebyshevT[j, k+1]^2, {j,n}]];
    T[n_, k_, m_]= b[n,m]/(b[k,m]*b[n-k,m]);
    Table[T[n, k, 2], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jul 03 2021 *)
    (* Second program *)
    T[n_, k_, m_]:= T[n, k, m]= Product[(1 - ChebyshevT[2*j+2*k, m+1])/(1 - ChebyshevT[2*j, m+1]), {j, n-k}];
    Table[T[n,k,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jul 03 2021 *)
  • Sage
    def b(n, k): return factorial(n) if (k==0) else product( 1 - chebyshev_T(j, k+1)^2 for j in (1..n) )
    def T(n, k, m): return b(n,m)/(b(k,m)*b(n-k,m))
    flatten([[T(n, k, 2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 03 2021

Formula

T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 2.
From G. C. Greubel, Jul 03 2021: (Start)
T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = (1/2^n)*Product_{j=1..n} (1 - ChebyshevT(2*j, k+1)), b(n, 0) = n!, and m = 2.
T(n, k, m) = Product_{j=1..n-k} ( (1 - ChebyshevT(2*j+2*k, m+1))/(1 - ChebyshevT(2*j, m+1)) ) with m = 2. (End)

Extensions

Edited by G. C. Greubel, Jul 03 2021

A156646 Triangle T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 10, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 484, 1, 1, 233289, 233289, 1, 1, 112444816, 54198633636, 112444816, 1, 1, 54198168025, 12591535188240100, 12591535188240100, 54198168025, 1, 1, 26123404543236, 2925290638056514680225, 1409984043580226203632400, 2925290638056514680225, 26123404543236, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 12 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,           1;
  1,         484,                 1;
  1,      233289,            233289,                 1;
  1,   112444816,       54198633636,         112444816,           1;
  1, 54198168025, 12591535188240100, 12591535188240100, 54198168025, 1;
		

Crossrefs

Cf. A007318 (m=0), A173585 (m=1), A156645 (m=2), this sequence (m=10).

Programs

  • Magma
    b:= func< n, k | n eq 0 select 1 else k eq 0 select Factorial(n) else (&*[1 - Evaluate(ChebyshevT(j), k+1)^2 : j in [1..n]]) >;
    T:= func< n,k,m | b(n,m)/(b(k,m)*b(n-k,m)) >;
    [T(n,k,10): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 03 2021
    
  • Mathematica
    (* First program *)
    b[n_, k_]:= b[n,k]= If[k==0, n!, Product[1 -ChebyshevT[j, k+1]^2, {j,n}]];
    T[n_, k_, m_]= b[n,m]/(b[k,m]*b[n-k,m]);
    Table[T[n,k,10], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jul 03 2021 *)
    (* Second program *)
    T[n_, k_, m_]:= T[n, k, m]= Product[(1 - ChebyshevT[2*j+2*k, m+1])/(1 - ChebyshevT[2*j, m+1]), {j, n-k}];
    Table[T[n,k,12], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jul 03 2021 *)
  • Sage
    def b(n, k): return factorial(n) if (k==0) else product( 1 - chebyshev_T(j, k+1)^2 for j in (1..n) )
    def T(n, k, m): return b(n,m)/(b(k,m)*b(n-k,m))
    flatten([[T(n, k, 10) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 03 2021

Formula

T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 10.
From G. C. Greubel, Jul 03 2021: (Start)
T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = (1/2^n)*Product_{j=1..n} (1 - ChebyshevT(2*j, k+1)), b(n, 0) = n!, and m = 10.
T(n, k, m) = Product_{j=1..n-k} ( (1 - ChebyshevT(2*j+2*k, m+1))/(1 - ChebyshevT(2*j, m+1)) ) with m = 10. (End)

Extensions

Edited by G. C. Greubel, Jul 03 2021
Showing 1-2 of 2 results.