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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,6
COMMENTS
Subset of A243995.
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
Sequence in context: A322093 A277681 A140876 * A036044 A335790 A078991
KEYWORD
nonn,easy
AUTHOR
Paolo P. Lava, Jun 19 2014
STATUS
approved

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Last modified May 22 02:24 EDT 2024. Contains 372741 sequences. (Running on oeis4.)