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.

A258311 Row sums of A258310.

Original entry on oeis.org

1, 1, 3, 7, 26, 86, 392, 1660, 9065, 46705, 297984, 1805926, 13186497, 91788477, 754481662, 5924676900, 54092804430, 472512732558, 4739696836485, 45540919862179, 497377234156959, 5208759709993591, 61475622078245542, 696384168181553136, 8825761698420052542
Offset: 0

Views

Author

Alois P. Heinz, May 25 2015

Keywords

Crossrefs

Cf. A258310.

Programs

  • Maple
    b:= proc(x, y, t, k) option remember; `if`(y>x or y<0, 0,
          `if`(x=0, 1, b(x-1, y-1, false, k)*`if`(t, (k*x+y)/y, 1)
                      +b(x-1, y, false, k) +b(x-1, y+1, true, k)))
        end:
    A:= (n, k)-> b(n, 0, false, k):
    T:= proc(n, k) option remember;
           add(A(n, i)*(-1)^(k-i)*binomial(k, i), i=0..k)/k!
        end:
    a:= proc(n) option remember; add(T(n, k), k=0..n/2) end:
    seq(a(n), n=0..30);
  • Mathematica
    b[x_, y_, t_, k_] := b[x, y, t, k] = If[y > x || y < 0, 0,
         If[x == 0, 1, b[x - 1, y - 1, False, k]*If[t, (k*x + y)/y, 1]
                     + b[x - 1, y, False, k] + b[x - 1, y + 1, True, k]]];
    A[n_, k_] := b[n, 0, False, k];
    T[n_, k_] := Sum[A[n, i] (-1)^(k - i) Binomial[k, i], {i, 0, k}]/k!;
    a[n_] := Sum[T[n, k], {k, 0, n/2}];
    Table[a[n], {n, 0, 30}] (* Jean-François Alcover, May 01 2022, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=0..floor(n/2)} A258310(n,k).

A258307 T(n,k) = 1/k! * Sum_{i=0..k} (-1)^(k-i) *C(k,i) * A258306(n,i); triangle T(n,k), n>=0, 0<=k<=floor(n/2), read by rows.

Original entry on oeis.org

1, 1, 2, 1, 5, 2, 14, 9, 1, 43, 28, 3, 141, 114, 21, 1, 490, 421, 82, 4, 1785, 1750, 442, 38, 1, 6789, 7114, 1941, 180, 5, 26809, 30854, 9868, 1210, 60, 1, 109632, 134239, 46337, 6191, 335, 6, 462755, 609276, 235035, 37321, 2700, 87, 1, 2012441, 2800134, 1157603, 199424, 15806, 560, 7
Offset: 0

Views

Author

Alois P. Heinz, May 25 2015

Keywords

Examples

			Triangle T(n,k) begins:
:     1;
:     1;
:     2,     1;
:     5,     2;
:    14,     9,    1;
:    43,    28,    3;
:   141,   114,   21,    1;
:   490,   421,   82,    4;
:  1785,  1750,  442,   38,  1;
:  6789,  7114, 1941,  180,  5;
: 26809, 30854, 9868, 1210, 60, 1;
		

Crossrefs

Column k=0 gives A258312.
Row sums give A258308.

Programs

  • Maple
    b:= proc(x, y, t, k) option remember; `if`(y>x or y<0, 0,
          `if`(x=0, 1, b(x-1, y-1, false, k)*`if`(t, (x+k*y)/y, 1)
                      +b(x-1, y, false, k) +b(x-1, y+1, true, k)))
        end:
    A:= (n, k)-> b(n, 0, false, k):
    T:= proc(n, k) option remember;
           add(A(n, i)*(-1)^(k-i)*binomial(k, i), i=0..k)/k!
        end:
    seq(seq(T(n, k), k=0..n/2), n=0..13);
  • Mathematica
    b[x_, y_, t_, k_] := b[x, y, t, k] = If[y > x || y < 0, 0, If[x == 0, 1, b[x - 1, y - 1, False, k]*If[t, (x + k*y)/y, 1] + b[x - 1, y, False, k] + b[x - 1, y + 1, True, k]]];
    A[n_, k_] :=  b[n, 0, False, k];
    T[n_, k_] := T[n, k] = Sum[A[n, i]*(-1)^(k-i)*Binomial[k, i], {i, 0, k}]/ k!;
    Table[T[n, k], {n, 0, 13}, {k, 0, n/2}] // Flatten (* Jean-François Alcover, Jun 06 2018, from Maple *)

A258309 A(n,k) is the sum over all Motzkin paths of length n of products over all peaks p of (k*x_p+y_p)/y_p, where x_p and y_p are the coordinates of peak p; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 4, 7, 9, 1, 1, 5, 10, 23, 21, 1, 1, 6, 13, 43, 71, 51, 1, 1, 7, 16, 69, 151, 255, 127, 1, 1, 8, 19, 101, 261, 703, 911, 323, 1, 1, 9, 22, 139, 401, 1485, 2983, 3535, 835, 1, 1, 10, 25, 183, 571, 2691, 6973, 14977, 13903, 2188
Offset: 0

Views

Author

Alois P. Heinz, May 25 2015

Keywords

Examples

			Square array A(n,k) begins:
:  1,   1,   1,    1,    1,    1,    1, ...
:  1,   1,   1,    1,    1,    1,    1, ...
:  2,   3,   4,    5,    6,    7,    8, ...
:  4,   7,  10,   13,   16,   19,   22, ...
:  9,  23,  43,   69,  101,  139,  183, ...
: 21,  71, 151,  261,  401,  571,  771, ...
: 51, 255, 703, 1485, 2691, 4411, 6735, ...
		

Crossrefs

Columns k=0-1 give: A001006, A140456(n+2).
Main diagonal gives A261785.

Programs

  • Maple
    b:= proc(x, y, t, k) option remember; `if`(y>x or y<0, 0,
          `if`(x=0, 1, b(x-1, y-1, false, k)*`if`(t, (k*x+y)/y, 1)
                      +b(x-1, y, false, k) +b(x-1, y+1, true, k)))
        end:
    A:= (n, k)-> b(n, 0, false, k):
    seq(seq(A(n, d-n), n=0..d), d=0..12);
  • Mathematica
    b[x_, y_, t_, k_] := b[x, y, t, k] = If[y > x || y < 0, 0, If[x == 0, 1, b[x - 1, y - 1, False, k]*If[t, (k*x + y)/y, 1] + b[x - 1, y, False, k] + b[x - 1, y + 1, True, k]]];
    A[n_, k_] := b[n, 0, False, k];
    Table[A[n, d - n], {d, 0, 12}, {n, 0, d}] // Flatten (* Jean-François Alcover, May 04 2017, translated from Maple *)

Formula

A(n,k) = Sum_{i=0..min(floor(n/2),k)} C(k,i) * i! * A258310(n,i).
Showing 1-3 of 3 results.