

A127471


Triangle formed from the matrix product A051731 * A054522 of infinite lower triangular matrices, read by rows.


1



1, 2, 1, 2, 0, 2, 3, 2, 0, 2, 2, 0, 0, 0, 4, 4, 2, 4, 0, 0, 2, 2, 0, 0, 0, 0, 0, 6, 4, 3, 0, 4, 0, 0, 0, 4, 3, 0, 4, 0, 0, 0, 0, 0, 6, 4, 2, 0, 8, 0, 0, 0, 0, 4
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OFFSET

1,2


COMMENTS

Left column = (1, 2, 2, 3, 2, 4,...) = d(n), A000005; right border = (1, 1, 2, 2, 4, 2, 6,...) = phi(n), A000010; row sums = (1, 3, 4, 7, 6, 12,...) = sigma(n), A000203.


LINKS

Table of n, a(n) for n=1..54.


EXAMPLE

First few rows of the triangle are:
1;
2, 1;
2, 0, 2;
3, 2, 0, 2;
2, 0, 0, 0, 4;
4, 2, 4, 0, 0, 2;
2, 0, 0, 0, 0, 0, 6;
4, 3, 0, 4, 0, 0, 0, 4;
3, 0, 4, 0, 0, 0, 0, 0, 6;
4, 2, 0, 0, 8, 0, 0, 0, 0, 4;
...


CROSSREFS

Cf. A054522, A051731, A000005, A000203, A000010.
Sequence in context: A335904 A144736 A137423 * A309044 A240312 A339898
Adjacent sequences: A127468 A127469 A127470 * A127472 A127473 A127474


KEYWORD

nonn,tabl


AUTHOR

Gary W. Adamson, Jan 15 2007


EXTENSIONS

Edited by N. J. A. Sloane, Aug 11 2019


STATUS

approved



