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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
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, 40, 36, 0, 28, 48, 30, 60, 36, 52, 44, 90, 36, 56, 52, 80, 40, 48, 42, 72, 72, 64, 46, 120, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10080

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..117800

FORMULA

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

PROG

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

CROSSREFS

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

Cf. A001599 (positions of zeros).

Sequence in context: A321908 A130728 A276085 * A324349 A092384 A061915

Adjacent sequences:  A324119 A324120 A324121 * A324123 A324124 A324125

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 15 2019

STATUS

approved

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Last modified April 26 08:05 EDT 2019. Contains 322472 sequences. (Running on oeis4.)