

A127571


Triangle T(n,k) = phi(n/k)*sigma(k) if k divides n, else 0.


0



1, 1, 3, 2, 0, 4, 2, 3, 0, 7, 4, 0, 0, 0, 6, 2, 6, 4, 0, 0, 12, 6, 0, 0, 0, 0, 0, 8, 4, 6, 0, 7, 0, 0, 0, 15, 6, 0, 8, 0, 0, 0, 0, 0, 13, 4, 12, 0, 0, 6, 0, 0, 0, 0, 18
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OFFSET

1,3


LINKS

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


FORMULA

T(n,k) = sum_{j=k..n} A054523(n,j)* A130208(j,k), product of the two infinite lower triangular matrices.
T(n,1) = A000010(n).
T(n,n) = A000203(n).


EXAMPLE

First few rows of the triangle are:
1;
1, 3;
2, 0, 4;
2, 3, 0, 7;
4, 0, 0, 0, 6;
2, 6, 4, 0, 0, 12;
...


CROSSREFS

Cf. A000203, A000010, A038040 (row sums), A054523.
Sequence in context: A005874 A129239 A224825 * A194662 A143612 A011231
Adjacent sequences: A127568 A127569 A127570 * A127572 A127573 A127574


KEYWORD

nonn,tabl


AUTHOR

Gary W. Adamson, Jan 19 2007


STATUS

approved



