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A323880 Number of divisors d > 1 of n such that A003415(d) divides n, where A003415 gives the arithmetic derivative of n. 1
0, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 3, 2, 2, 1, 4, 1, 2, 2, 3, 1, 4, 1, 3, 2, 2, 2, 4, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 5, 1, 3, 2, 3, 1, 4, 2, 3, 2, 2, 1, 5, 1, 2, 2, 3, 2, 3, 1, 3, 2, 4, 1, 5, 1, 2, 2, 3, 2, 3, 1, 3, 2, 2, 1, 4, 2, 2, 2, 3, 1, 5, 2, 3, 2, 2, 2, 6, 1, 3, 2, 4, 1, 3, 1, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

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

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

FORMULA

a(n) = Sum_{d|n, d>1} [A003415(d)|n], where [ ] is the Iverson bracket, and A003415 gives the arithmetic derivative of n.

PROG

(PARI)

A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415

A323880(n) = sumdiv(n, d, (d>1)&&!(n%A003415(d)));

CROSSREFS

Cf. A003415.

Cf. also A173441, A323878, A323879.

Sequence in context: A167679 A051881 A081757 * A033107 A239061 A309025

Adjacent sequences:  A323877 A323878 A323879 * A323881 A323882 A323883

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 07 2019

STATUS

approved

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Last modified January 23 13:40 EST 2020. Contains 331171 sequences. (Running on oeis4.)