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A127505 Triangle T(n,k) = mobius(n/k)*phi(k) if k|n, otherwise T(n,k)=0; 1<=k<=n. 0
1, -1, 1, -1, 0, 2, 0, -1, 0, 2, -1, 0, 0, 0, 4, 1, -1, -2, 0, 0, 2, -1, 0, 0, 0, 0, 0, 6, 0, 0, 0, -2, 0, 0, 0, 4, 0, 0, -2, 0, 0, 0, 0, 0, 6, 1, -1, 0, 0, -4, 0, 0, 0, 0, 4, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 1, 0, -2, 0, -2, 0, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..74.

FORMULA

T(n,k) = sum_{j=k..n} A054525(n,j)*A130207(j,k), 1<=k<=n.

EXAMPLE

First few rows of the triangle are:

1;

-1, 1;

-1, 0, 2;

0, -1, 0, 2;

-1, 0, 0, 0, 4;

1, -1, -2, 0, 0, 2;

...

CROSSREFS

Cf. A051731, A000010 (diagonal n=k), A007431 (row sums), A008683 (column k=1).

Sequence in context: A110914 A219200 A193527 * A194923 A321103 A086372

Adjacent sequences:  A127502 A127503 A127504 * A127506 A127507 A127508

KEYWORD

easy,tabl,sign

AUTHOR

Gary W. Adamson, Jan 17 2007

STATUS

approved

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Last modified January 17 14:57 EST 2020. Contains 330958 sequences. (Running on oeis4.)