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A070610 Number of positive integers k such that sigma(k) divides sigma(n). 2
1, 2, 2, 2, 3, 6, 3, 3, 2, 5, 6, 5, 3, 10, 10, 3, 5, 4, 3, 8, 5, 9, 10, 12, 3, 8, 5, 8, 5, 18, 5, 4, 13, 7, 13, 4, 2, 12, 8, 10, 8, 19, 3, 15, 6, 18, 13, 7, 3, 5, 18, 5, 7, 21, 18, 21, 7, 10, 12, 27, 4, 19, 6, 2, 15, 26, 3, 13, 19, 26, 18, 6, 2, 7, 7, 8, 19, 27, 7, 9, 2, 13, 15, 14, 13, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sigma(n)

FORMULA

a(n) = A074754(A000203(n)). - Antti Karttunen, Nov 17 2017

PROG

(PARI) for(n=1, 150, print1(sum(i=1, 10*n, if((sigma(n))%(sigma(i)), 0, 1)), ", "))

(PARI) A070610(n) = { my(s=sigma(n)); sum(k=1, s, !(s%sigma(k))); }; \\ Antti Karttunen, Nov 17 2017

CROSSREFS

Cf. A000203, A070242, A071181, A074754.

Sequence in context: A022867 A268595 A299019 * A156820 A104346 A318238

Adjacent sequences:  A070607 A070608 A070609 * A070611 A070612 A070613

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 13 2002

EXTENSIONS

Offset corrected, name edited by Antti Karttunen, Nov 17 2017

STATUS

approved

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Last modified June 19 14:08 EDT 2021. Contains 345140 sequences. (Running on oeis4.)