The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A082344 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A082344

Denominator of sopfr(n)/n, where sopfr=A001414 is the sum of prime factors (with repetition).
(history; published version)

#14 by N. J. A. Sloane at Sat Dec 04 12:33:33 EST 2021

STATUS

proposed

approved

#13 by Jean-François Alcover at Fri Dec 03 04:09:45 EST 2021

STATUS

editing

proposed

Discussion

Fri Dec 03

04:13

Michel Marcus: what is the difference with previous code ?

10:05

Jean-François Alcover: Not very different: It's just a bit clearer (no "flatten") and it uses the notation used in name.

#12 by Jean-François Alcover at Fri Dec 03 04:09:35 EST 2021

MATHEMATICA

sopfr[n_] := If[n == 1, 0, Total[Times @@@ FactorInteger[n]]];

a[n_] := Denominator[sopfr[n]/n];

Array[a, 100] (* Jean-François Alcover, Dec 03 2021 *)

STATUS

approved

editing

#11 by Harvey P. Dale at Tue Jul 24 20:41:22 EDT 2018

STATUS

editing

approved

#10 by Harvey P. Dale at Tue Jul 24 20:41:19 EDT 2018

MATHEMATICA

sopd[n_]:=Module[{f=Flatten[Table[#[[1]], #[[2]]]&/@FactorInteger[n]]}, Denominator[ Total[f]/n]]; Array[sopd, 90] (* Harvey P. Dale, Jul 24 2018 *)

STATUS

approved

editing

#9 by Susanna Cuyler at Sun Mar 04 10:35:06 EST 2018

STATUS

proposed

approved

#8 by Michel Marcus at Sun Mar 04 07:49:38 EST 2018

STATUS

editing

proposed

#7 by Michel Marcus at Sun Mar 04 07:49:28 EST 2018

EXAMPLE

n=200: (2+2+2+5+5)/(2*2*2*5*5) = 16/(2*2*2*5*5) = (2*2*2*2)/(2*2*2*5*5) = 2/25, therefore a(200)=25, A082343(200)=2.

(2*2*2*2)/(2*2*2*5*5) = 2/25, therefore a(200)=25, A082343(200)=2.

STATUS

proposed

editing

#6 by Antti Karttunen at Sun Mar 04 07:08:28 EST 2018

STATUS

editing

proposed

#5 by Antti Karttunen at Sun Mar 04 06:20:36 EST 2018

LINKS

Antti Karttunen, <a href="/A082344/b082344.txt">Table of n, a(n) for n = 1..65537</a>