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.

A193591 Augmentation of the Euler partition triangle A026820. See Comments.

Original entry on oeis.org

1, 1, 2, 1, 4, 7, 1, 7, 19, 31, 1, 10, 45, 103, 161, 1, 14, 82, 297, 617, 937, 1, 18, 146, 652, 2057, 4005, 5953, 1, 23, 228, 1395, 5251, 15004, 27836, 40668, 1, 28, 355, 2555, 13023, 43470, 115110, 205516, 295922, 1, 34, 509, 4689, 27327, 122006, 371942
Offset: 0

Views

Author

Clark Kimberling, Jul 31 2011

Keywords

Comments

For an introduction to the unary operation "augmentation" as applied to triangular arrays or sequences of polynomials, see A193091.

Examples

			First 5 rows:
  1
  1...2
  1...4...7
  1...7...19...31
  1...10..45...103...161
		

Crossrefs

Cf. A014616 (column 1), A026820, A193091.

Programs

  • Mathematica
    p[n_, k_] := Length@IntegerPartitions[n + 1,
       k + 1] (* A026820, Euler partition triangle *)
    Table[p[n, k], {n, 0, 5}, {k, 0, n}]
    m[n_] := Table[If[i <= j, p[n + 1 - i, j - i], 0], {i, n}, {j, n + 1}]
    TableForm[m[4]]
    w[0, 0] = 1; w[1, 0] = p[1, 0]; w[1, 1] = p[1, 1];
    v[0] = w[0, 0]; v[1] = {w[1, 0], w[1, 1]};
    v[n_] := v[n - 1].m[n]
    TableForm[Table[v[n], {n, 0, 12}]]  (* A193591 *)
    Flatten[Table[v[n], {n, 0, 9}]]