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.

A193631 Augmentation of the triangle given by p(n,k)=(3+(-1)^k)/2 for 0<=k<=n. See Comments.

Original entry on oeis.org

1, 2, 1, 4, 4, 5, 8, 12, 22, 17, 16, 32, 72, 88, 89, 32, 80, 208, 328, 474, 417, 64, 192, 560, 1056, 1836, 2364, 2253, 128, 448, 1440, 3120, 6168, 9684, 13038, 11937, 256, 1024, 3584, 8704, 19040, 34240, 54800, 71152, 66737, 512, 2304, 8704, 23296
Offset: 0

Views

Author

Clark Kimberling, Aug 01 2011

Keywords

Comments

For an introduction to the unary operation "augmentation" as applied to triangular arrays or sequences of polynomials, see A193091.
(column 2 of A193631)=A001787.

Examples

			First five rows of the triangle P=p(n,k):
2
2...1
2...1...2
2...1...2...1
2...1...2...1...2
First five rows of A193631:
1
2....1
4....4....5
8....12...22...17
16...32...72...88...89
		

Crossrefs

Programs

  • Mathematica
    p[n_, k_] := (3 + (-1)^k)/2;
    Table[p[n, k], {n, 0, 7}, {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, 6}]] (* A193631 *)
    Flatten[Table[v[n], {n, 0, 8}]]