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.

A258220 T(n,k) = 1/k! * Sum_{i=0..k} (-1)^(k-i) *C(k,i) * A258219(n,i); triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 1, 1, 4, 6, 1, 25, 49, 15, 1, 208, 498, 217, 28, 1, 2146, 6016, 3360, 635, 45, 1, 26368, 84042, 56728, 13997, 1475, 66, 1, 375733, 1332661, 1046619, 316281, 43974, 2954, 91, 1, 6092032, 23660034, 21053089, 7479444, 1283817, 114576, 5334, 120, 1
Offset: 0

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Author

Alois P. Heinz, May 23 2015

Keywords

Examples

			Triangle T(n,k) begins:
:     1;
:     1,     1;
:     4,     6,     1;
:    25,    49,    15,     1;
:   208,   498,   217,    28,    1;
:  2146,  6016,  3360,   635,   45,  1;
: 26368, 84042, 56728, 13997, 1475, 66, 1;
		

Crossrefs

Column k=0 gives A005411 (for n>0).
Main diagonal and lower diagonal give: A000012, A000384(n+1).
Row sums give A258221.
T(2n,n) gives A292692.

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+1, true, k)  ))
        end:
    A:= (n, k)-> b(2*n, 0, false, k):
    T:= (n, k)-> add(A(n, i)*(-1)^(k-i)*binomial(k, i), i=0..k)/k!:
    seq(seq(T(n, k), k=0..n), n=0..10);
  • 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+1, True, k]]]; A[n_, k_] := b[2*n, 0, False, k]; T [n_, k_] := Sum[A[n, i]*(-1)^(k-i)*Binomial[k, i], {i, 0, k}]/k!; Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Feb 20 2017, translated from Maple *)

Formula

T(n,k) = 1/k! * Sum_{i=0..k} (-1)^(k-i) *C(k,i) * A258219(n,i).