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A145580 Eigentriangle, row sums = A000930 2
1, 1, 1, 0, 1, 2, -1, 0, 2, 3, 0, -1, 0, 3, 4, 1, 0, -2, 0, 4, 6, 0, 1, 0, -3, 0, 6, 9, -1, 0, 2, 0, -4, 0, 9, 13, 0, -1, 0, 3, 0, -6, 0, 13, 19, 1, 0, -2, 0, 4, 0, -9, 0, 19, 28 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

Row sums = A000930 starting with offset 1: (1, 1, 2, 3, 4, 6, 9, 13, 19,...).

Sum of n-th row terms = rightmost term of next row.

LINKS

Table of n, a(n) for n=1..55.

FORMULA

Let M = an infinite lower triangular matrix with (1, 1, 0, -1, 0, 1, 0, -1, 0, 1,...) in every column; and X = an infinite lower triangular matrix with A000930 as the main diagonal (offset 1): (1, 1, 2, 3, 4, 6, 9, 13, 19,...) and the rest zeros. Triangle A145580 = M * X.

EXAMPLE

First few rows of the triangle =

1;

1, 1;

0, 1, 2;

-1, 0, 2, 3;

0, -1, 0, 3, 4;

1, 0, -2, 0, 4, 6;

0, 1, 0, -3, 0, 6, 9;

-1, 0, 2, 0, -4, 0, 9, 13;

0, -1, 0, 3, 0, -6, 0, 13, 19;

1, 0, -2, 0, 4, 0, -9, 0, 19, 28;

...

Row 6 = (1, 0, -2, 0, 4, 6) = termwise products of (1, 0, -1, 0, 1, 1) and (1, 1, 2, 3, 4, 6).

CROSSREFS

A000930

Sequence in context: A308321 A097854 A161515 * A144219 A144027 A019591

Adjacent sequences:  A145577 A145578 A145579 * A145581 A145582 A145583

KEYWORD

tabl,sign

AUTHOR

Gary W. Adamson, Oct 13 2008

STATUS

approved

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Last modified May 16 10:30 EDT 2021. Contains 343941 sequences. (Running on oeis4.)