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A324122 a(n) = sigma(n) - gcd(n*d(n), sigma(n)), where d(n) = number of divisors of n (A000005) and sigma(n) = sum of divisors of n (A000203). 4

%I

%S 0,2,2,6,4,0,6,14,12,16,10,24,12,16,12,30,16,36,18,36,28,32,22,48,30,

%T 40,36,0,28,48,30,60,36,52,44,90,36,56,52,80,40,48,42,72,72,64,46,120,

%U 54,90,60,96,52,96,68,112,76,88,58,144,60,88,102,126,80,96,66,120,84,128,70,192,72,112,122,136,92,144,78,184,120,124,82

%N a(n) = sigma(n) - gcd(n*d(n), sigma(n)), where d(n) = number of divisors of n (A000005) and sigma(n) = sum of divisors of n (A000203).

%H Antti Karttunen, <a href="/A324122/b324122.txt">Table of n, a(n) for n = 1..10080</a>

%H Antti Karttunen, <a href="/A324122/a324122.txt">Data supplement: n, a(n) computed for n = 1..117800</a>

%F a(n) = A000203(n) - A324121(n) = A000203(n) - gcd(A000203(n), A038040(n)).

%o (PARI) A324122(n) = (sigma(n) - gcd(sigma(n),n*numdiv(n)));

%Y Cf. A000005, A000203, A038040, A106315, A106316, A324045, A324046, A324047, A324121.

%Y Cf. A001599 (positions of zeros).

%K nonn

%O 1,2

%A _Antti Karttunen_, Feb 15 2019

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Last modified August 11 23:45 EDT 2020. Contains 336434 sequences. (Running on oeis4.)