A079550 - OEIS

A079550

Array T(m,n) = phi(m^2)*phi(n^2) - phi(m*n)^2 (m,n >= 1), read by antidiagonals.

0, 1, 1, 2, 0, 2, 4, 8, 8, 4, 4, 0, 0, 0, 4, 8, 24, 32, 32, 24, 8, 6, 8, 56, 0, 56, 8, 6, 16, 48, 36, 96, 96, 36, 48, 16, 18, 0, 108, 32, 0, 32, 108, 0, 18, 24, 72, 128, 192, 176, 176, 192, 128, 72, 24, 10, 16, 0, 0, 264, 0, 264, 0, 0, 16, 10, 32, 120, 176, 288, 384, 360, 360, 384, 288

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OFFSET

1,4

COMMENTS

It is known that phi(m^2)*phi(n^2) >= phi(m*n)^2.

REFERENCES

József Sándor, Dragoslav S. Mitrinovic, and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter I, p. 9, section I.2.2.

LINKS

Table of n, a(n) for n=1..75.

EXAMPLE

Array begins:

m\n | 1 2 3 4 5 6 ...

----+--------------------------------

1 | 0 1 2 4 4 8 ...

2 | 1 0 8 0 24 8 ...

3 | 2 8 0 32 56 36 ...

4 | 4 0 32 0 96 32 ...

5 | 4 24 56 96 0 176 ...

6 | 8 8 36 32 176 0 ...