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 10 results.

A026754 a(n) = Sum{k=0..n} T(n,k), T given by A026747.

Original entry on oeis.org

1, 2, 5, 10, 24, 48, 114, 228, 540, 1080, 2558, 5116, 12133, 24266, 57658, 115316, 274600, 549200, 1310817, 2621634, 6271788, 12543576, 30076629, 60153258, 144550655, 289101310, 696176322, 1392352644, 3359516328
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(add(A026747(n,k), k=0..n), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[Sum[T[n, k],{k,0,n}], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [sum(T(n, k) for k in (0..n)) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A026748 a(n) = T(2n,n), T given by A026747.

Original entry on oeis.org

1, 3, 11, 44, 184, 790, 3452, 15278, 68290, 307696, 1395696, 6367199, 29193025, 134442102, 621609060, 2884432810, 13428450520, 62703991531, 293606387095, 1378309455352, 6485734373020, 30586630485443, 144544075759391, 684395988590939
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(A026747(2*n,n), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[T[2n, n], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [T(2*n, n) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A026750 a(n) = T(2n,n-2), T given by A026747.

Original entry on oeis.org

1, 9, 58, 329, 1753, 9020, 45442, 225860, 1112543, 5446607, 26550968, 129042976, 625860205, 3031021096, 14664729519, 70906318405, 342717456708, 1656208470644, 8003645557573, 38681730323747, 186985728069661, 904119336235884
Offset: 2

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(A026747(2*n,n-2), n=2..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[T[2n, n-2], {n,2,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [T(2*n, n-2) for n in (2..30)] # G. C. Greubel, Oct 29 2019

A026751 a(n) = T(2n-1,n-1), T given by A026747.

Original entry on oeis.org

1, 4, 17, 74, 327, 1461, 6584, 29879, 136391, 625731, 2883357, 13338421, 61920497, 288368511, 1346873365, 6307694990, 29613690966, 139352892908, 657163401162, 3105304341356, 14701236957028, 69722518168060, 331220099616432
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(A026747(2*n-1,n-1), n=1..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[T[2n-1, n-1], {n,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [T(2*n-1, n-1) for n in (1..30)] # G. C. Greubel, Oct 29 2019

A026752 a(n) = T(2n-1,n-2), T given by A026747.

Original entry on oeis.org

1, 7, 39, 201, 1000, 4885, 23621, 113543, 543895, 2600204, 12417829, 59278440, 282969385, 1351124510, 6454283276, 30849969965, 147555219782, 706274470775, 3383203356648, 16219148141581, 77817618006364, 373661751926702
Offset: 2

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(A026747(2*n-1,n-2), n=2..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[T[2n-1, n-2], {n,2,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [T(2*n-1, n-2) for n in (2..30)] # G. C. Greubel, Oct 29 2019

A026753 a(n) = T(n, floor(n/2)), T given by A026747.

Original entry on oeis.org

1, 1, 3, 4, 11, 17, 44, 74, 184, 327, 790, 1461, 3452, 6584, 15278, 29879, 68290, 136391, 307696, 625731, 1395696, 2883357, 6367199, 13338421, 29193025, 61920497, 134442102, 288368511, 621609060, 1346873365, 2884432810
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(A026747(n,floor(n/2)), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[T[n, Floor[n/2]], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [T(n, floor(n/2)) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A026755 a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026747.

Original entry on oeis.org

1, 1, 4, 5, 18, 25, 84, 124, 398, 612, 1901, 3012, 9126, 14800, 43968, 72658, 212417, 356544, 1028520, 1749344, 4989477, 8583258, 24244139, 42121079, 117973702, 206754379, 574811040, 1015179978, 2803969443, 4986329826
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(add(A026747(n,k), k=0..floor(n/2)), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[Sum[T[n, k], Floor[n/2]], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [sum(T(n, k) for k in (0..floor(n/2))) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A026756 a(n) = Sum_{i=0..n} Sum_{j=0..n} T(i,j), T given by A026747.

Original entry on oeis.org

1, 3, 8, 18, 42, 90, 204, 432, 972, 2052, 4610, 9726, 21859, 46125, 103783, 219099, 493699, 1042899, 2353716, 4975350, 11247138, 23790714, 53867343, 114020601, 258571256, 547672566, 1243848888, 2636201532, 5995717860
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if n<0 then 0;
       elif k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(add(add(A026747(i,j), j=0..n), i=0..n), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[n<0, 0, If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]]; Table[Sum[T[i, j], {i,0,n},{j,0,n}], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (n<0): return 0
        elif (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [sum(sum(T(i,j) for j in (0..n)) for i in (0..n)) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A026757 a(n) = Sum_{k=0..floor(n/2)} T(n-k,k), T given by A026747.

Original entry on oeis.org

1, 1, 2, 4, 6, 11, 20, 32, 58, 102, 169, 302, 527, 888, 1573, 2741, 4661, 8215, 14316, 24481, 43023, 74998, 128747, 225867, 393838, 678047, 1188201, 2072239, 3575728, 6261248, 10921278, 18879372, 33040083, 57637061
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    A026747 := proc(n,k) option remember;
       if k=0 or k = n then 1;
       elif type(n,'even') and k <= n/2 then
            procname(n-1,k-1)+procname(n-2,k-1)+procname(n-1,k) ;
       else
           procname(n-1,k-1)+procname(n-1,k) ;
       end if ;
    end proc:
    seq(add(A026747(n-k,k), k=0..floor(n/2)), n=0..30); # G. C. Greubel, Oct 29 2019
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[EvenQ[n] && k<=n/2, T[n-1, k -1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]; Table[Sum[T[n-k, k], {k,0,Floor[n/2]}], {n,0,30}] (* G. C. Greubel, Oct 29 2019 *)
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0 or k==n): return 1
        elif (mod(n,2)==0 and k<=n/2): return T(n-1,k-1) + T(n-2,k-1) + T(n-1,k)
        else: return T(n-1,k-1) + T(n-1,k)
    [sum(T(n-k, k) for k in (0..floor(n/2))) for n in (0..30)] # G. C. Greubel, Oct 29 2019

A210381 Triangle by rows, derived from the beheaded Pascal's triangle, A074909.

Original entry on oeis.org

1, 0, 2, 0, 1, 3, 0, 1, 3, 4, 0, 1, 4, 6, 5, 0, 1, 5, 10, 10, 6, 0, 1, 6, 15, 20, 15, 7, 0, 1, 7, 21, 35, 35, 21, 8, 0, 1, 8, 28, 56, 70, 56, 28, 9, 0, 1, 9, 36, 84, 126, 126, 84, 36, 10, 0, 1, 10, 45, 120, 210, 252, 210, 120, 45, 11
Offset: 0

Views

Author

Roger L. Bagula and Gary W. Adamson, Mar 20 2012

Keywords

Comments

Row sums of the triangle = 2^n.
Let the triangle = an infinite lower triangular matrix, M. Then M * The Bernoulli numbers, A027641/A027642 as a vector V = [1, -1, 0, 0, 0,...]. M * the Bernoulli sequence variant starting [1, 1/2, 1/6,...] = [1, 1, 1,...]. M * 2^n: [1, 2, 4, 8,...] = A027649. M * 3^n = A255463; while M * [1, 2, 3,...] = A047859, and M * A027649 = A027650.
Row sums of powers of the triangle generate the Poly-Bernoulli number sequences shown in the array of A099594. - Gary W. Adamson, Mar 21 2012
Triangle T(n,k) given by (0, 1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, -1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 25 2012

Examples

			{1},
{0, 2},
{0, 1, 3},
{0, 1, 3, 4},
{0, 1, 4, 6, 5},
{0, 1, 5, 10, 10, 6},
{0, 1, 6, 15, 20, 15, 7},
{0, 1, 7, 21, 35, 35, 21, 8},
{0, 1, 8, 28, 56, 70, 56, 28, 9},
{0, 1, 9, 36, 84, 126, 126, 84, 36, 10},
{0, 1, 10, 45, 120, 210, 252, 210, 120, 45, 11}
...
		

References

  • Konrad Knopp, Elements of the Theory of Functions, Dover, 1952,pp 117-118.

Crossrefs

Programs

  • Mathematica
    t2[n_, m_] = If[m - 1 <= n, Binomial[n, m - 1], 0];
    O2 = Table[Table[If[n == m, t2[n, m] + 1, t2[n, m]], {m, 0, n}], {n, 0, 10}];
    Flatten[O2]

Formula

Partial differences of the beheaded Pascal's triangle A074909 starting from the top, by columns.
G.f.: (1-x)/(1-x-2*y*x+y*x^2+y^2*x^2). - Philippe Deléham, Mar 25 2012
T(n,k) = T(n-1,k) + 2*T(n-1,k-1) - T(n-2,k-1) - T(n-2,k-2), T(0,0) = T(2,1) = 1, T(1,0) = T(2,0) = 0, T(1,1) = 2, T(2,2) = 3 and T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Mar 25 2012
Showing 1-10 of 10 results.