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.

A176339 Triangle T(n,k) = 1 - A176337(k) - A176337(n-k) + A176337(n) read by rows.

Original entry on oeis.org

1, 1, 1, 1, -3, 1, 1, 17, 17, 1, 1, -239, -219, -239, 1, 1, 7169, 6933, 6933, 7169, 1, 1, -444479, -437307, -437563, -437307, -444479, 1, 1, 56004353, 55559877, 55567029, 55567029, 55559877, 56004353, 1, 1, -14225105663, -14169101307, -14169545803, -14169538395, -14169545803, -14169101307, -14225105663, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 15 2010

Keywords

Comments

Row sums are {1, 2, -1, 36, -695, 28206, -2201133, 334262520, -99297043939, 57953303599938, -66678973493759897, ...}.

Examples

			Triangle begins as:
  1;
  1,       1;
  1,      -3,       1;
  1,      17,      17,       1;
  1,    -239,    -219,    -239,       1;
  1,    7169,    6933,    6933,    7169,       1;
  1, -444479, -437307, -437563, -437307, -444479, 1;
		

Crossrefs

Programs

  • GAP
    b:= function(n,q)
        if n=0 then return 0;
        else return 1 - (q^n-1)*b(n-1,q);
        fi; end;
    T:= function(n,k,q) return 1 + b(n,q) - b(n-k,q) - b(k,q); end;
    Flat(List([0..10], n-> List([0..n], k-> T(n,k,2) ))); # G. C. Greubel, Dec 07 2019
  • Magma
    function b(n,q)
      if n eq 0 then return 0;
      else return 1 - (q^n-1)*b(n-1,q);
      end if; return b; end function;
    function T(n,k,q) return 1 + b(n,q) - b(n-k,q) - b(k,q); end function;
    [ T(n,k,2) : k in [0..n], n in [0..10]]; // G. C. Greubel, Dec 07 2019
    
  • Maple
    A176339 := proc(n,m)
        1-A176337(m)-A176337(n-m)+A176337(n) ;
    end proc: # R. J. Mathar, May 04 2013
  • Mathematica
    b[n_, q_]:= b[n, q]= If[n==0, 0, (1-q^n)*b[n-1, q] +1];
    T[n_,k_,q_]:= 1 + b[n,q] -b[n-k,q] - b[k,q];
    Table[T[n,k,2], {n,0,10}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Dec 07 2019 *)
  • PARI
    b(n,q) = if(n==0, 0, 1 + (1-q^n)*b(n-1,q) );
    T(n,k,q) = 1 + b(n,q) - b(n-k,q) - b(k,q);
    for(n=0,10, for(k=0,n, print1(T(n,k,2), ", "))) \\ G. C. Greubel, Dec 07 2019
    
  • Sage
    @CachedFunction
    def b(n, q):
        if (n==0): return 0
        else: return 1 - (q^n-1)*b(n-1,q)
    def T(n,k,q): return 1 + b(n,q) - b(n-k,q) - b(k,q)
    [[T(n,k,2) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Dec 07 2019
    

Formula

T(n,k) = T(n,n-k).

A176338 a(n) = 1 + (1-3^n)*a(n-1) for n >=1, a(0) = 0.

Original entry on oeis.org

0, 1, -7, 183, -14639, 3542639, -2579041191, 5637784043527, -36983863325537119, 727916397973221576159, -42982007467522787629036631, 7614090694841791737333323035127, -4046432358866721800888421193787892879
Offset: 0

Views

Author

Roger L. Bagula, Apr 15 2010

Keywords

Crossrefs

Cf. A176337.

Programs

  • GAP
    a:= function(n,q)
        if n=0 then return 0;
        else return 1 - (q^n-1)*a(n-1,q);
    fi; end; List([0..15], n-> a(n,3) ); # G. C. Greubel, Dec 07 2019
  • Magma
    function a(n,q)
      if n eq 0 then return 0;
      else return 1 - (q^n-1)*a(n-1,q);
      end if; return a; end function;
    [a(n,3): n in [0..15]]; // G. C. Greubel, Dec 07 2019
    
  • Maple
    A176338 := proc(n)
        if n = 0 then
            0;
        else
            1+(1-3^n)*procname(n-1) ;
        end if;
    end proc: # R. J. Mathar, May 04 2013
  • Mathematica
    a[n_, q_]:= a[n, q]= If[n==0, 0, (1-q^n)*a[n-1, q] +1]; Table[a[n, 3], {n,0,15}]
    nxt[{n_,a_}]:={n+1,a(1-3^(n+1))+1}; NestList[nxt,{0,0},20][[;;,2]] (* Harvey P. Dale, Dec 31 2024 *)
  • PARI
    q=3; a(n,q) = if(n==0, 0, 1 -(q^n-1)*a(n-1,q) );
    vector(16, n, a(n-1,3)) \\ G. C. Greubel, Dec 07 2019
    
  • Sage
    def a(n, q):
        if (n==0): return 0
        else: return 1 - (q^n-1)*a(n-1,q)
    [a(n,3) for n in (0..15)] # G. C. Greubel, Dec 07 2019
    

A176340 Triangle T(n,k) = 1 - A176338(k) - A176338(n-k) + A176338(n) read by rows.

Original entry on oeis.org

1, 1, 1, 1, -8, 1, 1, 190, 190, 1, 1, -14822, -14624, -14822, 1, 1, 3557278, 3542464, 3542464, 3557278, 1, 1, -2582583830, -2579026544, -2579041556, -2579026544, -2582583830, 1, 1, 5640363084718, 5637780500896, 5637784057984, 5637784057984, 5637780500896, 5640363084718, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 15 2010

Keywords

Comments

Row sums are: {1, 2, -6, 382, -44266, 14199486, -12902262302, 33831855287198,
-258898313695820850, 5823405140242006622494, -386839522966544578870468774, ...}.

Examples

			Triangle starts as:
  1;
  1,       1;
  1,      -8,       1;
  1,     190,     190,       1;
  1,  -14822,  -14624,  -14822,       1;
  1, 3557278, 3542464, 3542464, 3557278, 1;
		

Crossrefs

Programs

  • GAP
    b:= function(n,q)
        if n=0 then return 0;
        else return 1 - (q^n-1)*b(n-1,q);
        fi; end;
    T:= function(n,k,q) return 1 + b(n,q) - b(n-k,q) - b(k,q); end;
    Flat(List([0..10], n-> List([0..n], k-> T(n,k,3) ))); # G. C. Greubel, Dec 07 2019
  • Magma
    function b(n,q)
      if n eq 0 then return 0;
      else return 1 - (q^n-1)*b(n-1,q);
      end if; return b; end function;
    function T(n,k,q) return 1 + b(n,q) - b(n-k,q) - b(k,q); end function;
    [ T(n,k,3) : k in [0..n], n in [0..10]]; // G. C. Greubel, Dec 07 2019
    
  • Mathematica
    b[n_, q_]:= b[n, q]= If[n==0, 0, (1-q^n)*b[n-1, q] +1];
    T[n_,k_,q_]:= 1 + b[n,q] -b[n-k,q] - b[k,q];
    Table[T[n,k,3], {n,0,10}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Dec 07 2019 *)
  • PARI
    b(n,q) = if(n==0, 0, 1 + (1-q^n)*b(n-1,q) );
    T(n,k,q) = 1 + b(n,q) - b(n-k,q) - b(k,q);
    for(n=0,10, for(k=0,n, print1(T(n,k,3), ", "))) \\ G. C. Greubel, Dec 07 2019
    
  • Sage
    @CachedFunction
    def b(n, q):
        if (n==0): return 0
        else: return 1 - (q^n-1)*b(n-1,q)
    def T(n,k,q): return 1 + b(n,q) - b(n-k,q) - b(k,q)
    [[T(n,k,3) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Dec 07 2019
    

Formula

T(n,k) = T(n,n-k).

Extensions

Edited by G. C. Greubel, Dec 07 2019
Showing 1-3 of 3 results.