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 32 results. Next

A103452 Inverse of number triangle A103451.

Original entry on oeis.org

1, -1, 1, -1, 0, 1, -1, 0, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

Paul Barry, Feb 06 2005

Keywords

Comments

Triangle T(n,k), 0 <= k <= n, read by rows given by [ -1, 2, 0, 0, 0, 0, 0, ...] DELTA [1, 0, -1/2, 1/2, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938. - Philippe Deléham, May 01 2007

Examples

			Triangle begins
   1;
  -1, 1;
  -1, 0, 1;
  -1, 0, 0, 1;
  -1, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
Production matrix begins
  -1, 1;
  -2, 1, 1;
  -2, 1, 0, 1;
  -2, 1, 0, 0, 1;
  -2, 1, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 0, 0, 1;
		

Crossrefs

Cf. A000007 (row sums), A103453, A103454, A103455.

Programs

Formula

T(n,k) = 1 if k = n, -1 if k = 0, otherwise 0.
Sum_{k=0..n} T(n, k) = 0^n (row sums).
Sum_{k=0..floor(n/2)} T(n-k, k) = 0^n - (1-(-1)^n)/2 (diagonal sums).
G.f.: (1 - 2*x + y*x^2)/((1-x)*(1-y*x)). - Philippe Deléham, Feb 11 2012

A132047 3*A007318 - 2*A103451 as infinite lower triangular matrices.

Original entry on oeis.org

1, 1, 1, 1, 6, 1, 1, 9, 9, 1, 1, 12, 18, 12, 1, 1, 15, 30, 30, 15, 1, 1, 18, 45, 60, 45, 18, 1, 1, 21, 63, 105, 105, 63, 21, 1, 1, 24, 84, 168, 210, 168, 84, 24, 1, 1, 27, 108, 252, 378, 378, 252, 108, 27, 1, 1, 30, 135, 360, 630, 756, 630, 360, 135, 30, 1
Offset: 0

Views

Author

Gary W. Adamson, Aug 08 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  1, 6, 1;
  1, 9, 9, 1;
  1, 12, 18, 12, 1;
  1, 15, 30, 30, 15, 1;
  1, 18, 45, 60, 45, 18, 1;
  ...
		

Crossrefs

Cf. A007318, A103451, A131128 (row sums).

Programs

  • PARI
    T(n, k) = my(bnk = binomial(n, k)); 3*bnk - 2*(bnk==1); \\ Michel Marcus, Jun 16 2022

Formula

a(n) = 3*A007318(n) - 2*A103451(n).
T(n,k) = 3*C(n,k)-2*(C(n,k-n)+C(n,-k)-C(0,n+k)), 0<=k<=n. [Eric Werley, Jul 01 2011]

Extensions

Corrected and extended by Roger L. Bagula, Nov 02 2008

A132823 A007318 + 2*A103451 - 2*A000012.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 4, 2, 1, 1, 3, 8, 8, 3, 1, 1, 4, 13, 18, 13, 4, 1, 1, 5, 19, 33, 33, 19, 5, 1, 1, 6, 26, 54, 68, 54, 26, 6, 1, 1, 7, 34, 82, 124, 124, 82, 34, 7, 1, 1, 8, 43, 118, 208, 250, 208, 118, 43, 8, 1, 1, 9, 53, 163, 328, 460, 460, 328, 163, 53, 9, 1
Offset: 0

Views

Author

Gary W. Adamson, Sep 02 2007

Keywords

Comments

Row sums = A132824: (1, 2, 2, 4, 10, 24, 54, 116, 242, ...).

Examples

			First few rows of the triangle:
  1;
  1, 1;
  1, 0,  1;
  1, 1,  1,  1;
  1, 2,  4,  2,   1;
  1, 3,  8,  8,   3,   1;
  1, 4, 13, 18,  13,   4,  1;
  1, 5, 19, 33,  33,  19,  5,  1;
  1, 6, 26, 54,  68,  54, 26,  6, 1;
  1, 7, 34, 82, 124, 124, 82, 34, 7, 1;
  ...
		

Crossrefs

A(2n,n) gives A115112 for n>0.

Formula

A007318 + 2*A103451 - 2*A000012 as infinite lower triangular matrices.

Extensions

One missing 1 inserted and more terms added by Alois P. Heinz, Feb 10 2019

A135226 Triangle A135225 + A007318 - A103451, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 4, 5, 1, 1, 5, 9, 7, 1, 1, 6, 14, 16, 9, 1, 1, 7, 20, 30, 25, 11, 1, 1, 8, 27, 50, 55, 36, 13, 1, 1, 9, 35, 77, 105, 91, 49, 15, 1, 1, 10, 44, 112, 182, 196, 140, 64, 17, 1, 1, 11, 54, 156, 294, 378, 336, 204, 81, 19, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

Row sums = A083329: (1, 2, 5, 11, 23, 47, 95, ...).

Examples

			First few rows of the triangle:
  1;
  1, 1;
  1, 3,  1;
  1, 4,  5,  1;
  1, 5,  9,  7,  1;
  1, 6, 14, 16,  9,  1;
  1, 7, 20, 30, 25, 11,  1;
  1, 8, 27, 50, 55, 36, 13, 1;
...
		

Crossrefs

Programs

  • GAP
    T:= function(n,k)
        if k=0 or k=n then return 1;
        else return ((n+k)/n)*Binomial(n,k);
        fi; end;
    Flat(List([0..10], n-> List([0..n], k-> T(n,k) ))); # G. C. Greubel, Nov 20 2019
  • Magma
    T:= func< n,k | k eq 0 or k eq n select 1 else ((n+k)/n)*Binomial(n,k) >;
    [T(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    T:= proc(n, k) option remember;
          if k=0 or k=n then 1
        else ((n+k)/n)*binomial(n,k)
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..10); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, ((n+k)/n) Binomial[n, k]]; Table[T[n, k], {n,0,10}, {k,0,n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==0 || k==n, 1, ((n+k)/n)*binomial(n,k)); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    @CachedFunction
    def T(n,k):
        if (k==0 or k==n): return 1
        else: return ((n+k)/n)*binomial(n, k)
    [[T(n,k) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Nov 20 2019
    

Formula

T(n,k) = A135225(n,k) + A007318(n,k) - A103451(n,k) as infinite lower triangular matrices.
T(n,k) = ((n+k)/n)*binomial(n,k) with T(n,0) = T(n,n) = 1. - G. C. Greubel, Nov 20 2019

Extensions

Corrected and extended by Philippe Deléham, Nov 14 2011

A134868 A103451 * A002260.

Original entry on oeis.org

1, 2, 2, 2, 2, 3, 2, 2, 3, 4, 2, 2, 3, 4, 5, 2, 2, 3, 4, 5, 6, 2, 2, 3, 4, 5, 6, 7, 2, 2, 3, 4, 5, 6, 7, 8, 2, 2, 3, 4, 5, 6, 7, 8, 9, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
Offset: 1

Views

Author

Gary W. Adamson, Nov 14 2007

Keywords

Comments

Row sums = A134869: (1, 4, 7, 11, 16, 22, 29, ...).

Examples

			First few rows of the triangle:
  1;
  2, 2;
  2, 2, 3;
  2, 2, 3, 4;
  2, 2, 3, 4, 5;
  ...
		

Crossrefs

Programs

  • Mathematica
    Table[k + Boole[k == 1 && n != 2], {n, 2, 14}, {k, n - 1}] // Flatten (* Michael De Vlieger, Jul 19 2016 *)

Formula

A103451 * A002260 as infinite lower triangular matrices.
Left border of A002260, (1, 1, 1, 1, ...) is replaced by (1, 2, 2, 2, ...).

A135223 Triangle A000012 * A127648 * A103451, read by rows.

Original entry on oeis.org

1, 3, 2, 6, 2, 3, 10, 2, 3, 4, 15, 2, 3, 4, 5, 21, 2, 3, 4, 5, 6, 28, 2, 3, 4, 5, 6, 7, 36, 2, 3, 4, 5, 6, 7, 8, 45, 2, 3, 4, 5, 6, 7, 8, 9, 55, 2, 3, 4, 5, 6, 7, 8, 9, 10, 66, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 78, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 91, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
Offset: 1

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

Row sums = A028387.

Examples

			First few rows of the triangle are:
   1;
   3, 2;
   6, 2, 3;
  10, 2, 3, 4;
  15, 2, 3, 4, 5;
...
		

Crossrefs

Programs

  • GAP
    T:= function(n,k)
        if k=1 then return Binomial(n+1,2);
        else return k;
        fi; end;
    Flat(List([1..15], n-> List([1..n], k-> T(n,k) ))); # G. C. Greubel, Nov 20 2019
  • Magma
    [k eq 1 select Binomial(n+1,2) else k: k in [1..n], n in [1..15]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    seq(seq( `if`(k=1, binomial(n+1,2), k), k=1..n), n=1..15); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==1, Binomial[n+1, 2], k]; Table[T[n, k], {n, 15}, {k,n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==1, binomial(n+1,2), k); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    @CachedFunction
    def T(n,k):
        if (k==1): return binomial(n+1, 2)
        else: return k
    [[T(n,k) for k in (1..n)] for n in (1..15)] # G. C. Greubel, Nov 20 2019
    

Formula

T(n,k) = A000012(n,k) * A127648(n,k) * A103451(n,k) as infinite lower triangular matrices. Replace left border of 1's in A002260 with (1, 3, 6, 10, 15, ...).
T(n, k) = k with T(n,1) = binomial(n+1, 2). - G. C. Greubel, Nov 20 2019

Extensions

More terms added by G. C. Greubel, Nov 20 2019

A135224 Triangle A103451 * A007318 * A000012, read by rows. T(n, k) for 0 <= k <= n.

Original entry on oeis.org

1, 3, 1, 5, 3, 1, 9, 7, 4, 1, 17, 15, 11, 5, 1, 33, 31, 26, 16, 6, 1, 65, 63, 57, 42, 22, 7, 1, 129, 127, 120, 99, 64, 29, 8, 1, 257, 255, 247, 219, 163, 93, 37, 9, 1, 513, 511, 502, 466, 382, 256, 130, 46, 10, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

Row sums = A132750: (1, 4, 9, 21, 49, 113, ...).
Left border = A083318: (1, 3, 5, 9, 17, 33, ...).

Examples

			First few rows of the triangle:
   1;
   3,  1;
   5,  3,  1;
   9,  7,  4,  1;
  17, 15, 11,  5,  1;
  33, 31, 26, 16,  6,  1;
  65, 63, 57, 42, 22,  7,  1;
...
		

Crossrefs

Programs

  • Magma
    function T(n,k)
      if k eq 0 and n eq 0 then return 1;
      elif k eq 0 then return 2^n +1;
      else return (&+[Binomial(n, k+j): j in [0..n]]);
      end if; return T; end function;
    [T(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    T:= proc(n, k) option remember;
          if k=0 and n=0 then 1
        elif k=0 then 2^n +1
        else add(binomial(n, k+j), j=0..n)
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..10); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k] = If[k==n==0, 1, If[k==0, 2^n +1, Sum[Binomial[n, k + j], {j, 0, n}]]]; Table[T[n, k], {n, 0, 10}, {k, 0, n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==0 && n==0, 1, if(k==0, 2^n +1, sum(j=0, n, binomial(n, k+j)) )); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    def T(n, k):
        if (k==0 and n==0): return 1
        elif (k==0): return 2^n + 1
        else: return sum(binomial(n, k+j) for j in (0..n))
    [[T(n, k) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Nov 20 2019

Formula

T(n, k) = A103451(n,k) * A007318(n,k) * A000012(n,k) as infinite lower triangular matrices.
T(n, k) = Sum_{j=0..n} binomial(n, k+j), with T(0,0) = 1 and T(n,0) = 2^n + 1. - G. C. Greubel, Nov 20 2019
T(n, k) = binomial(n, k)*hypergeom([1, k-n], [k+1], -1) - binomial(n, k+n+1)* hypergeom([1, k+1], [k+n+2], -1) + 0^k - 0^n. - Peter Luschny, Nov 20 2019

A135228 Triangle A000012(signed) * A007318 * A103451, read by rows.

Original entry on oeis.org

1, 1, 1, 3, 1, 1, 5, 2, 2, 1, 11, 2, 4, 3, 1, 21, 3, 6, 7, 4, 1, 43, 3, 9, 13, 11, 5, 1, 85, 4, 12, 22, 24, 16, 6, 1, 171, 4, 16, 34, 46, 40, 22, 7, 1, 341, 5, 20, 50, 80, 86, 62, 29, 8, 1, 683, 5, 25, 70, 130, 166, 148, 91, 37, 9, 1, 1365, 6, 30, 95, 200, 296, 314, 239, 128, 46, 10, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

Row sums = A000975: (1, 2, 5, 10, 21, 42, 85, 170, ...).
Left border = A001045: (1, 1, 3, 5, 11, 21, 43, ...).

Examples

			First few rows of the triangle are:
    1;
    1, 1;
    3, 1,  1;
    5, 2,  2,  1;
   11, 2,  4,  3,  1;
   21, 3,  6,  7,  4,  1;
   43, 3,  9, 13, 11,  5,  1;
   85, 4, 12, 22, 24, 16,  6, 1;
  171, 4, 16, 34, 46, 40, 22, 7, 1;
...
		

Crossrefs

Programs

  • Magma
    function T(n,k)
      if k eq 0 then return (2^(n+1) +(-1)^n)/3;
      else return (&+[Binomial(n-2*j-1, k-1): j in [0..Floor((n-1)/2)]]);
      end if; return T; end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    T:= proc(n, k) option remember;
          if k=0 then (2^(n+1) +(-1)^n)/3
        else add(binomial(n-2*j-1, k-1), j=0..floor((n-1)/2))
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..12); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0, (2^(n+1) +(-1)^n)/3, Sum[Binomial[n-1-2*j, k-1], {j,0,Floor[(n-1)/2]}]]; Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==0, (2^(n+1) +(-1)^n)/3, sum(j=0, (n-1)\2, binomial( n-2*j-1, k-1)) ); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0): return (2^(n+1) +(-1)^n)/3
        else: return sum(binomial(n-2*j-1, k-1) for j in (0..floor((n-1)/2)))
    [[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Nov 20 2019

Formula

T(n,k) = A000012(signed) * A007318 * A103451 as infinite lower triangular matrices. A000012(signed) = (1; -1,1; 1,-1,1; ...).
T(n,k) = Sum_{j=0..floor((n-1)/2)} binomial(n-2*j-1, k-1), with T(n,0) =
(2^(n+1) - (-1)^(n+1))/3 (Jacobsthal_{n+1}).- G. C. Greubel, Nov 20 2019

Extensions

Offset changed by G. C. Greubel, Nov 20 2019

A135229 Triangle A000012(signed) * A103451 * A007318, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 4, 3, 1, 1, 3, 6, 7, 4, 1, 1, 3, 9, 13, 11, 5, 1, 1, 4, 12, 22, 24, 16, 6, 1, 1, 4, 16, 34, 46, 40, 22, 7, 1, 1, 5, 20, 50, 80, 86, 62, 29, 8, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

row sums = A005578 starting (1, 2, 3, 6, 11, 22, 43, 86, ...).

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  1, 1,  1;
  1, 2,  2,  1;
  1, 2,  4,  3,  1;
  1, 3,  6,  7,  4,  1;
  1, 3,  9, 13, 11,  5,  1;
  1, 4, 12, 22, 24, 16,  6, 1;
  1, 4, 16, 34, 46, 40, 22, 7, 1;
...
		

Crossrefs

Programs

  • Magma
    function T(n,k)
      if k eq 0 then return 1;
      else return (&+[Binomial(n-2*j-1, k-1): j in [0..Floor((n-1)/2)]]);
      end if; return T; end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    T:= proc(n, k) option remember;
          if k=0 then 1
        else add(binomial(n-2*j-1, k-1), j=0..floor((n-1)/2))
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..12); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0, 1, Sum[Binomial[n-1-2*j, k-1], {j, 0, Floor[(n-1)/2]}]]; Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==0, 1, sum(j=0, (n-1)\2, binomial( n-2*j-1, k-1)) ); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0): 1
        else: return sum(binomial(n-2*j-1, k-1) for j in (0..floor((n-1)/2)))
    [[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Nov 20 2019

Formula

T(n,k) = A000012(signed) * A103451 * A007318 as infinite lower triangular matrices, where A000012(signed) = (1; -1,1; 1,-1,1; ...).
T(n,k) = Sum_{j=0..floor((n-1)/2)} binomial(n-2*j-1, k-1), with T(n,0) = 1. - G. C. Greubel, Nov 20 2019

Extensions

Offset changed by G. C. Greubel, Nov 20 2019

A135230 Triangle A103451 * A000012(signed) * A007318, read by rows.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 2, 2, 4, 3, 1, 1, 3, 6, 7, 4, 1, 2, 3, 9, 13, 11, 5, 1, 1, 4, 12, 22, 24, 16, 6, 1, 2, 4, 16, 34, 46, 40, 22, 7, 1, 1, 5, 20, 50, 80, 86, 62, 29, 8, 1, 2, 5, 25, 70, 130, 166, 148, 91, 37, 9, 1, 1, 6, 30, 95, 200, 296, 314, 239, 128, 46, 10, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 23 2007

Keywords

Comments

row sums = A135231

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  2, 1,  1;
  1, 2,  2,  1;
  2, 2,  4,  3,  1;
  1, 3,  6,  7,  4,  1;
  2, 3,  9, 13, 11,  5,  1;
  1, 4, 12, 22, 24, 16,  6, 1;
  2, 4, 16, 34, 46, 40, 22, 7, 1;
...
		

Crossrefs

Programs

  • Magma
    function T(n,k)
      if k eq n then return 1;
      elif k eq 0 then return (3+(-1)^n)/2;
      else return (&+[Binomial(n-2*j-1, k-1): j in [0..Floor((n-1)/2)]]);
      end if; return T; end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Nov 20 2019
    
  • Maple
    T:= proc(n, k) option remember;
          if k=n then 1
        elif k=0 then (3+(-1)^n)/2
        else add(binomial(n-2*j-1, k-1), j=0..floor((n-1)/2))
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..12); # G. C. Greubel, Nov 20 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==n, 1, If[k==0, (3+(-1)^n)/2, Sum[Binomial[n-1 - 2*j, k-1], {j, 0, Floor[(n-1)/2]}] ]]; Table[T[n, k], {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, Nov 20 2019 *)
  • PARI
    T(n,k) = if(k==n, 1, if(k==0, (3+(-1)^n)/2, sum(j=0, (n-1)\2, binomial( n-2*j-1, k-1)) )); \\ G. C. Greubel, Nov 20 2019
    
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==n): return 1
        elif (k==0): return (3+(-1)^n)/2
        else: return sum(binomial(n-2*j-1, k-1) for j in (0..floor((n-1)/2)))
    [[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Nov 20 2019

Formula

T(n,k) = A103451 * A000012(signed) * A007318, where A000012(signed) = (1; -1,1; 1,-1,1;...).
T(n,k) = Sum_{j=0..floor((n-1)/2)} binomial(n-2*j-1, k-1), with T(n,0) = (3+(-1)^n)/2 and T(n,n) = 1. - G. C. Greubel, Nov 20 2019

Extensions

More terms and offset changed by G. C. Greubel, Nov 20 2019
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