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.

A259786 Number T(n,k) of n X n Tesler matrices of nonnegative integers with element sum n+k; triangle T(n,k), n>=1, 0<=k<=n*(n-1)/2, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 2, 1, 1, 6, 11, 11, 7, 3, 1, 1, 10, 35, 65, 81, 71, 50, 27, 12, 4, 1, 1, 15, 85, 260, 526, 771, 878, 811, 627, 416, 238, 118, 50, 18, 5, 1, 1, 21, 175, 805, 2436, 5362, 9123, 12568, 14465, 14289, 12345, 9483, 6534, 4071, 2297, 1176, 542, 224, 81, 25, 6, 1
Offset: 1

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Author

Alois P. Heinz, Jul 05 2015

Keywords

Comments

For the definition of Tesler matrices see A008608.

Examples

			Triangle T(n,k) begins:
  1;
  1,  1;
  1,  3,  2,   1;
  1,  6, 11,  11,   7,   3,   1;
  1, 10, 35,  65,  81,  71,  50,  27,  12,   4,   1;
  1, 15, 85, 260, 526, 771, 878, 811, 627, 416, 238, 118, 50, 18, 5, 1;
  ...
		

Crossrefs

Row sums give A008608.

Programs

  • Maple
    b:= proc(n, i, l) option remember; (m-> `if`(m=0, 1, expand(
          `if`(i=0, x^(l[1]+1)*b(l[1]+1, m-1, subsop(1=NULL, l)), add(
           b(n-j, i-1, subsop(i=l[i]+j, l)), j=0..n)))))(nops(l))
        end:
    T:= n->(p->seq(coeff(p, x, i), i=n-1..degree(p)))(b(1, n-1, [0$(n-1)])):
    seq(T(n), n=1..8);
  • Mathematica
    b[n_, i_, l_] := b[n, i, l] = Function[m, If[m == 0, 1, Expand[
         If[i == 0, x^(l[[1]] + 1)*b[l[[1]] + 1, m - 1,
         ReplacePart[l, 1 -> Nothing]], Sum[b[n - j, i - 1,
         ReplacePart[l, i -> l[[i]] + j]], {j, 0, n}]]]]][Length[l]];
    T[n_] := Function[p, Table[Coefficient[p, x, i], {i, n - 1,
         Exponent[p, x]}]][b[1, n - 1, Table[0, {n - 1}]]];
    Table[T[n], {n, 1, 8}] // Flatten (* Jean-François Alcover, Mar 18 2022, after Alois P. Heinz *)

Formula

Sum_{k=0..n*(n-1)/2} (n+k) * T(n,k) = A259787(n).