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.

A257673 Triangle T(n,k), n>=0, 0<=k<=n, read by rows: row n is the inverse binomial transform of the n-th row of array A255961, which has the Euler transform of (j->j*k) in column k.

Original entry on oeis.org

1, 0, 1, 0, 3, 1, 0, 6, 6, 1, 0, 13, 21, 9, 1, 0, 24, 62, 45, 12, 1, 0, 48, 162, 174, 78, 15, 1, 0, 86, 396, 576, 376, 120, 18, 1, 0, 160, 917, 1719, 1509, 695, 171, 21, 1, 0, 282, 2036, 4761, 5340, 3285, 1158, 231, 24, 1, 0, 500, 4380, 12441, 17234, 13473, 6309, 1792, 300, 27, 1
Offset: 0

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Author

Alois P. Heinz, May 03 2015

Keywords

Comments

T is the convolution triangle of the number of plane partitions (A000219). - Peter Luschny, Oct 19 2022

Examples

			Triangle T(n,k) begins:
  1;
  0,   1;
  0,   3,    1;
  0,   6,    6,    1;
  0,  13,   21,    9,    1;
  0,  24,   62,   45,   12,    1;
  0,  48,  162,  174,   78,   15,    1;
  0,  86,  396,  576,  376,  120,   18,   1;
  0, 160,  917, 1719, 1509,  695,  171,  21,  1;
  0, 282, 2036, 4761, 5340, 3285, 1158, 231, 24, 1;
  ...
		

Crossrefs

Columns k=0-10 give: A000007, A000219 (for n>0), A321947, A321948, A321949, A321950, A321951, A321952, A321953, A321954, A321955.
Main diagonal and lower diagonals give: A000012, A008585, A081266.
Row sums give A257674.
T(2n,n) give A257675.
Cf. A255961.

Programs

  • Maple
    A:= proc(n, k) option remember; `if`(n=0, 1, k*add(
          A(n-j, k)*numtheory[sigma][2](j), j=1..n)/n)
        end:
    T:= (n, k)-> add(A(n, k-i)*(-1)^i*binomial(k, i), i=0..k):
    seq(seq(T(n, k), k=0..n), n=0..12);
    # Uses function PMatrix from A357368.
    PMatrix(10, A000219); # Peter Luschny, Oct 19 2022
  • Mathematica
    A[n_, k_] := A[n, k] = If[n==0, 1, k*Sum[A[n-j, k]*DivisorSigma[2, j], {j, 1, n}]/n];
    T[n_, k_] := Sum[A[n, k-i]*(-1)^i*Binomial[k, i], {i, 0, k}];
    Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Mar 21 2017, translated from Maple *)

Formula

T(n,k) = Sum_{i=0..k} (-1)^i * C(k,i) * A255961(n,k-i).
G.f. of column k: (-1 + Product_{j>=1} 1 / (1 - x^j)^j)^k.