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.

A174026 Convolved with its aerated variant = (1, 2, 3, ...).

Original entry on oeis.org

1, 2, 1, 0, 2, 4, 2, 0, 1, 2, 1, 0, 0, 0, 0, 0, 2, 4, 2, 0, 4, 8, 4, 0, 2, 4, 2, 0, 0, 0, 0, 0, 1, 2, 1, 0, 2, 4, 2, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 2, 0, 4, 8, 4, 0, 2, 4, 2, 0, 0, 0, 0, 0, 4, 8, 4, 0, 8, 16, 8, 0, 4, 8, 4, 0, 0, 0, 0, 0, 2, 4
Offset: 1

Views

Author

Gary W. Adamson, Mar 06 2010

Keywords

Comments

Equals left border of triangle A174064.
With suitable polcoeff offsets, we obtain: (x * 2x^2 + x^3 + 2x^5) * (1 + 2x^2 + 4x^4 + 2x^8 + 4x^10 + ...) = (x + 2x^2 + 3x^3 + 4x^4 + 5x^5 + ...).

Examples

			First few rows of triangle A174064 = 1, 2, 1, 0, 2, 4, ... = heading terms, multiplied * left border.
  1;
  2,
  1, 2;
  0, 4;
  2, 2, 1;
  4, 0, 2;
  2, 4, 1, 0;
  0, 8, 0, 0;
  1, 4, 2, 0, 2;
  2, 0, 4, 0, 4;
  ...
where each successive column > 1 is shifted down twice, with terms filled in as a product of (1, 2, 1, 0, 2, 4, 2, ...) * (1, 2, 1, 0, 2, 4, 2, ...).
The next term in the series is generated in the ongoing left column, such that leftmost term = (n - sum of row n terms in columns > 1).
For example, a(9) = 1 since the terms to the right of the 1 in row 9 are (4, 2, 0, 2), sum = 8.
		

Crossrefs

Cf. A174064.

Formula

Left border of a multiplication table with columns >1 shifted down twice, with row sums = (1, 2, 3, ...); as shown in triangle A174064.

Extensions

More terms from R. J. Mathar, Mar 18 2010