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A326066 a(n) = sigma(n) - sigma(A032742(n)), where A032742 gives the largest proper divisor of n. 6
0, 2, 3, 4, 5, 8, 7, 8, 9, 12, 11, 16, 13, 16, 18, 16, 17, 26, 19, 24, 24, 24, 23, 32, 25, 28, 27, 32, 29, 48, 31, 32, 36, 36, 40, 52, 37, 40, 42, 48, 41, 64, 43, 48, 54, 48, 47, 64, 49, 62, 54, 56, 53, 80, 60, 64, 60, 60, 59, 96, 61, 64, 72, 64, 70, 96, 67, 72, 72, 96, 71, 104, 73, 76, 93, 80, 84, 112, 79, 96, 81, 84, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..20000

Index entries for sequences related to sigma(n)

FORMULA

a(n) = A000203(n) - A326065(n) = A000203(n) - A000203(A032742(n)).

a(1) = 0; for n > 1, if n is of the form p^k (p prime and exponent k >= 1), then a(n) = n, otherwise a(n) > n.

For terms in A247180, i.e., when n = A020639(n) * A032742(n), with the smallest prime factor A020639(n) unitary, a(n) = A020639(n) * A326065(n).

PROG

(PARI)

A032742(n) = if(1==n, n, n/vecmin(factor(n)[, 1]));

A326065(n) = sigma(A032742(n));

A326066(n) = (sigma(n) - sigma(A032742(n)));

CROSSREFS

Cf. A000203, A020639, A032742, A246655 (positions of fixed points), A247180, A326065, A326067, A326135, A326136.

Sequence in context: A094607 A258831 A098098 * A080785 A319605 A245822

Adjacent sequences:  A326063 A326064 A326065 * A326067 A326068 A326069

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jun 06 2019

STATUS

approved

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Last modified October 22 10:29 EDT 2021. Contains 348160 sequences. (Running on oeis4.)