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.

Showing 1-2 of 2 results.

A158951 Triangle read by rows, A051731 * A158948.

Original entry on oeis.org

1, 2, 1, 3, 0, 1, 4, 2, 0, 1, 4, 0, 1, 0, 1, 7, 2, 1, 1, 0, 1, 5, 0, 1, 0, 1, 0, 1, 8, 3, 0, 2, 0, 1, 0, 18, 0, 2, 0, 1, 0, 1, 0, 1, 10, 2, 1, 1, 1, 1, 0, 1, 0, 1
Offset: 1

Views

Author

Gary W. Adamson & Mats Granvik, Mar 31 2009

Keywords

Comments

Row sums = sigma(n), A000203. Left column = A079247

Examples

			First few rows of the triangle =
1;
2, 1;
3, 0, 1;
4, 2, 0, 1;
4, 0, 1, 0, 1;
7, 2, 1, 1, 0, 1;
5, 0, 1, 0, 1, 0, 1;
8, 3, 0, 2, 0, 1, 0, 1;
8, 0, 2, 0, 1, 0, 1, 0, 1;
10, 2, 1, 1, 1, 1, 0, 1, 0, 1;
7, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1;
15, 4, 1, 3, 0, 2, 0, 10, 1, 0, 1;
8, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1;
13, 2, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1;
...
		

Crossrefs

Formula

Triangle read by rows, A051731 * A158948

A158950 Triangle read by rows, A158948 * (an infinite lower triangular matrix with A000071 prefaced with a 1 as the right border; and the rest zeros).

Original entry on oeis.org

1, 1, 1, 2, 0, 2, 2, 1, 0, 4, 3, 0, 2, 0, 7, 3, 1, 0, 4, 0, 12, 4, 0, 2, 0, 7, 0, 20, 4, 1, 0, 4, 0, 12, 0, 33, 5, 0, 2, 0, 7, 0, 20, 0, 54, 5, 1, 0, 4, 0, 12, 0, 33, 0, 88, 6, 0, 2, 0, 7, 0, 20, 0, 54, 0, 143
Offset: 1

Views

Author

Gary W. Adamson, Mar 31 2009

Keywords

Comments

Row sums = A000071 starting with nonzero terms: (1, 2, 4, 7, 12,...) As a property of eigentriangles, sum of n-th row terms = rightmost term of next row.

Examples

			First few rows of the triangle =
1;
1, 1;
2, 0, 2;
2, 1, 0, 4;
3, 0, 2, 0, 7;
3, 1, 0, 4, 0, 12;
4, 0, 2, 0, 7, 0, 20;
4, 1, 0, 4, 0, 12, 0, 33;
5, 0, 2, 0, 7, 0, 20, 0, 54;
5, 1, 0, 4, 0, 12, 0, 33, 0, 88;
6, 0, 2, 0, 7, 0, 20, 0, 54, 0, 143;
6, 1, 0, 4, 0, 12, 0, 33, 0, 88, 0, 232;
7, 0, 2, 0, 7, 0, 20, 0, 54, 0, 143, 0, 376;
7, 1, 0, 4, 0, 12, 0, 33, 0, 88, 0, 232, 0, 609;
...
Row 4 = (2, 1, 0, 4) = termwise products of (2, 1, 0, 1) and (1, 1, 2, 4);
where (2, 1, 0, 1) = row 4 of triangle A158948, and (1, 1, 2, 4) = the 3 nonzero terms of A000071 prefaced with a 1.
		

Crossrefs

Formula

Triangle read by rows, A158948 * M; where M = (an infinite lower triangular matrix with A000071 prefaced with a 1 as the right border, and the rest zeros). M = (1; 0,1; 0,0,2; 0,0,0,4; 0,0,0,7;...).
Showing 1-2 of 2 results.