The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A284723

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Showing entries 1-10 | older changes

A284723

Smallest odd prime that is relatively prime to n.
(history; published version)

#24 by Michael De Vlieger at Mon Jul 25 15:52:40 EDT 2022

STATUS

proposed

approved

#23 by Amiram Eldar at Mon Jul 25 02:29:13 EDT 2022

STATUS

editing

proposed

#22 by Amiram Eldar at Mon Jul 25 02:24:04 EDT 2022

FORMULA

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{p odd prime} ((p*(p-1)/Product_{q odd prime <= p} q)) = 3.8401019546... . - Amiram Eldar, Jul 25 2022

MATHEMATICA

a[n_] := Module[{p = 3}, While[Divisible[n, p], p = NextPrime[p]]; p]; Array[a, 100] (* Amiram Eldar, Jul 25 2022 *)

STATUS

approved

editing

#21 by Michael De Vlieger at Mon Jul 18 10:01:12 EDT 2022

STATUS

proposed

approved

#20 by Antti Karttunen at Mon Jul 18 10:01:06 EDT 2022

STATUS

editing

proposed

#19 by Antti Karttunen at Mon Jul 18 06:09:27 EDT 2022

CROSSREFS

Cf. A007947, A020639, A053669, A284721.

#18 by Antti Karttunen at Mon Jul 18 06:06:49 EDT 2022

LINKS

Antti Karttunen, <a href="/A284723/b284723.txt">Table of n, a(n) for n = 1..100000</a>

#17 by Antti Karttunen at Mon Jul 18 06:02:53 EDT 2022

FORMULA

a(n) = A355001(2*n). - Antti Karttunen, Jul 18 2022

CROSSREFS

Even bisection of A355001.

STATUS

approved

editing

#16 by Michael De Vlieger at Mon Jun 13 10:43:56 EDT 2022

STATUS

proposed

approved

#15 by Michel Marcus at Mon Jun 13 10:29:39 EDT 2022

STATUS

editing

proposed