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.

A193738 Triangular array: the fusion of polynomial sequences P and Q given by p(n,x)=q(n,x)=x^n+x^(n-1)+...+x+1.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 2, 3, 3, 1, 2, 3, 4, 4, 1, 2, 3, 4, 5, 5, 1, 2, 3, 4, 5, 6, 6, 1, 2, 3, 4, 5, 6, 7, 7, 1, 2, 3, 4, 5, 6, 7, 8, 8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12, 1, 2, 3, 4
Offset: 0

Views

Author

Clark Kimberling, Aug 04 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.

Examples

			First six rows:
1
1....1
1....2....2
1....2....3....3
1....2....3....4...4
1....2....3....4...5...5
		

Crossrefs

Programs

  • Haskell
    a193738 n k = a193738_tabl !! n !! k
    a193738_row n = a193738_tabl !! n
    a193738_tabl = map reverse a193739_tabl
    -- Reinhard Zumkeller, May 11 2013
  • Mathematica
    z = 12;
    p[0, x_] := 1
    p[n_, x_] := x*p[n - 1, x] + 1; p[n_, 0] := p[n, x] /. x -> 0
    q[n_, x_] := p[n, x]
    t[n_, k_] := Coefficient[p[n, x], x^(n - k)];
    t[n_, n_] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]  (* A193738 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]   (* A193739 *)