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.

A265017 Total sum T(n,k) of number of lambda-parking functions of partitions lambda of n into distinct parts with smallest part k; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 0, 2, 0, 3, 0, 3, 0, 5, 0, 0, 4, 0, 7, 8, 0, 0, 5, 0, 25, 12, 0, 0, 0, 6, 0, 36, 16, 15, 0, 0, 0, 7, 0, 81, 20, 21, 0, 0, 0, 0, 8, 0, 107, 74, 27, 24, 0, 0, 0, 0, 9, 0, 316, 102, 33, 32, 0, 0, 0, 0, 0, 10, 0, 427, 222, 39, 40, 35, 0, 0, 0, 0, 0, 11
Offset: 0

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Author

Alois P. Heinz, Nov 30 2015

Keywords

Examples

			Triangle T(n,k) begins:
00 :  1;
01 :  0,   1;
02 :  0,   0,   2;
03 :  0,   3,   0,   3;
04 :  0,   5,   0,   0,  4;
05 :  0,   7,   8,   0,  0,  5;
06 :  0,  25,  12,   0,  0,  0, 6;
07 :  0,  36,  16,  15,  0,  0, 0, 7;
08 :  0,  81,  20,  21,  0,  0, 0, 0, 8;
09 :  0, 107,  74,  27, 24,  0, 0, 0, 0, 9;
10 :  0, 316, 102,  33, 32,  0, 0, 0, 0, 0, 10;
11 :  0, 427, 222,  39, 40, 35, 0, 0, 0, 0,  0, 11;
12 :  0, 869, 286, 153, 48, 45, 0, 0, 0, 0,  0,  0, 12;
		

Crossrefs

Row sums give A265016.
Column k=0 gives A000007.
Main diagonal gives A028310, first lower diagonal is A000004.
T(2n+1,n) gives A005563.
T(2n+2,n) gives A028347(n+2).
T(2n+3,n) gives A028560.

Programs

  • Maple
    p:= l-> (n-> n!*LinearAlgebra[Determinant](Matrix(n, (i, j)
             -> (t->`if`(t<0, 0, l[i]^t/t!))(j-i+1))))(nops(l)):
    g:= (n, i, l)-> `if`(i*(i+1)/2n, 0, g(n-i, i-1, [i, l[]])))):
    T:= n-> (f-> seq(coeff(f, x, i), i=0..n))(g(n$2, [])):
    seq(T(n), n=0..16);
  • Mathematica
    p[l_] := With[{n = Length[l]}, n!*Det[Table[Function[t,
         If[t < 0, 0, l[[i]]^t/t!]][j - i + 1], {i, n}, {j, n}]]];
    g[n_, i_, l_] := If[i(i+1)/2 < n, 0, If[n == 0, p[l]*x^
         If[l == {}, 0, l[[1]]], g[n, i - 1, l] +
         If[i > n, 0, g[n - i, i - 1, Prepend[l, i]]]]];
    T[n_] := If[n == 0, {1}, CoefficientList[g[n, n, {}], x]];
    Table[T[n], {n, 0, 16}] // Flatten (* Jean-François Alcover, Aug 20 2021, after Alois P. Heinz *)