



1, 2, 0, 2, 2, 0, 3, 0, 3, 0, 2, 2, 3, 4, 0, 4, 2, 0, 0, 5, 0, 2, 2, 3, 4, 5, 6, 0, 4, 0, 6, 0, 5, 0, 7, 0, 3, 4, 0, 4, 5, 0, 7, 8, 0, 4, 2, 6, 4, 0, 0, 7, 0, 9, 0, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 6, 2, 3, 0, 10, 0, 7, 0, 0, 0, 11, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
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OFFSET

1,2


COMMENTS

Left border = d(n).
Row sums = A057661: (1, 2, 4, 6, 11, 11, 22, 22, 31,...).


LINKS

Table of n, a(n) for n=1..89.


FORMULA

Triangle read by rows, A051731 * A127368, 1<=k<=n. A051731 = the inverse Mobius transform. A127368 records the reduced residue system mod n, by rows.


EXAMPLE

First few rows of the triangle =
1;
2, 0;
2, 2, 0;
3, 0, 3, 0;
2, 2, 3, 4, 0;
4, 2, 0, 0, 5, 0;
2, 2, 3, 4, 5, 6, 0;
...


CROSSREFS

Cf. A127368, A051731, A057661, A000005.
Sequence in context: A127800 A035692 A308654 * A208955 A121363 A214258
Adjacent sequences: A143610 A143611 A143612 * A143614 A143615 A143616


KEYWORD

nonn,tabl


AUTHOR

Gary W. Adamson, Aug 27 2008


STATUS

approved



