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A127476 Triangle T(n,k) = sum_{j=k..n, gcd(n,j)=1, k|j} phi(k). 0
1, 1, 0, 2, 1, 0, 2, 0, 2, 0, 4, 2, 2, 2, 0, 2, 0, 0, 0, 4, 0, 6, 3, 4, 2, 4, 2, 0, 4, 0, 2, 0, 4, 0, 6, 0, 6, 3, 0, 4, 4, 0, 6, 4, 0, 4, 0, 4, 0, 0, 0, 6, 0, 6, 0, 10, 5, 6, 4, 8, 2, 6, 4, 6, 4, 0, 4, 0, 0, 0, 4, 0, 6, 0, 0, 0, 10, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..78.

FORMULA

T(n,k) = sum_{j=k..n} A054521(n,j) * A054522(j,k), product of the two infinite lower triangular matrices.

T(n,1) = A000010(n).

EXAMPLE

First few rows of the triangle are:

1;

1, 0;

2, 1, 0;

2, 0, 2, 0;

4, 2, 2, 2, 0;

2, 0, 0, 0, 4, 0;

6, 3, 4, 2, 4, 2, 0;

4, 0, 2, 0, 4, 0, 6, 0;

...

CROSSREFS

Cf. A054521, A054522, A023896 (row sums), A000010.

Sequence in context: A244553 A231167 A194313 * A140397 A120614 A252055

Adjacent sequences:  A127473 A127474 A127475 * A127477 A127478 A127479

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jan 15 2007

STATUS

approved

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Last modified May 28 17:57 EDT 2017. Contains 287241 sequences.