

A243997


a(n) = phi(sigma(n)  phi(n)  d(n)), where phi(n) is the Euler totient function, sigma(n) the sum of divisors of n and d(n) the number of divisors of n.


1



1, 0, 0, 1, 0, 2, 0, 6, 2, 4, 0, 6, 0, 6, 4, 6, 0, 18, 0, 12, 8, 10, 0, 20, 4, 12, 6, 18, 0, 24, 0, 40, 8, 16, 8, 24, 0, 18, 12, 20, 0, 36, 0, 28, 16, 22, 0, 42, 4, 66, 12, 32, 0, 46, 12, 40, 16, 28, 0, 48, 0, 30, 30, 40, 16, 56, 0, 40, 16, 48, 0, 104, 0, 36
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OFFSET

1,6


COMMENTS

a(p)=0 if p is prime.


LINKS



EXAMPLE

sigma(72) = 195, phi(72) = 24, d(72) = 12 and phi(195  24  12) = 104.


MAPLE

with(numtheory): P:=proc(q) local n;
for n from 1 to q do print(phi(sigma(n)phi(n)tau(n)));
od; end: P(100);


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



