1,4

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.

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;...).

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.

A158948, A000071

Sequence in context: A159937 A058728 A143751 this_sequence A059581 A163542 A061895

Adjacent sequences: A158947 A158948 A158949 this_sequence A158951 A158952 A158953

eigen,nonn,tabl

Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 31 2009