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A128407 Triangle read by rows: T(n,n) = mobius(n) on the diagonal, zero elsewhere. 20
1, 0, -1, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A128407 * [1,2,3...] = n*mu(n), A055615: (1, -2, -3, 0, -5, 6, -7, 0,...). A051731 * A128407 = A054524. A128407 * A051731 = A128408.

LINKS

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

FORMULA

Infinite lower triangular matrix with mu(n), A008683, as the right border and the rest zeros.

EXAMPLE

First few rows of the triangle are:

1;

0, -1;

0, 0, -1;

0, 0, 0, 0;

0, 0, 0, 0, -1;

0, 0, 0, 0, 0, 1;

0, 0, 0, 0, 0, 0, -1;

...

CROSSREFS

Cf. A051731, A128408, A008683 (row sums and diagonal), A054524.

Sequence in context: A074381 A179560 A341602 * A134286 A023531 A320841

Adjacent sequences:  A128404 A128405 A128406 * A128408 A128409 A128410

KEYWORD

tabl,sign,easy

AUTHOR

Gary W. Adamson, Mar 01 2007

EXTENSIONS

Name improved . - R. J. Mathar, Aug 03 2015

STATUS

approved

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Last modified May 18 10:19 EDT 2021. Contains 343995 sequences. (Running on oeis4.)