The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A140523 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A140523

If the highest power of the prime p that divides n is p^b(n,p), then a(n) is the least nonnegative integer that equals some sum{p|n} (+or-)p^b(n, p).
(history; published version)

#13 by Michel Marcus at Fri Aug 28 08:06:54 EDT 2020

STATUS

reviewed

approved

#12 by Joerg Arndt at Fri Aug 28 08:01:00 EDT 2020

STATUS

proposed

reviewed

#11 by Jean-François Alcover at Fri Aug 28 06:59:31 EDT 2020

STATUS

editing

proposed

#10 by Jean-François Alcover at Fri Aug 28 06:59:21 EDT 2020

MATHEMATICA

f[n_] := Module[{F, V}, F = Power @@@ FactorInteger[n]; V = {F[[1]]}; Do[V = {# + F[[i]], # - F[[i]]}& /@ V // Flatten, {i, 2, Length[F]}]; V // Abs // Min];

f[1] = 0;

Array[f, 100] (* Jean-François Alcover, Aug 28 2020, after Robert Israel *)

STATUS

approved

editing

#9 by Bruno Berselli at Wed Sep 12 04:04:03 EDT 2018

STATUS

proposed

approved

#8 by Robert Israel at Wed Sep 12 03:59:24 EDT 2018

STATUS

editing

proposed

#7 by Robert Israel at Wed Sep 12 03:56:06 EDT 2018

LINKS

Robert Israel, <a href="/A140523/b140523.txt">Table of n, a(n) for n = 1..10000</a>

MAPLE

f:= proc(n) local F, V, i;

F:= map(t -> t[1]^t[2], ifactors(n)[2]);

V:= {F[1]};

for i from 2 to nops(F) do

V:= map(t -> (t+F[i], t-F[i]), V);

od:

min(map(abs, V))

end proc:

f(1):= 0:

map(f, [$1..100]); # Robert Israel, Sep 12 2018

STATUS

approved

editing

#6 by Charles R Greathouse IV at Wed Apr 09 10:15:19 EDT 2014

AUTHOR

Leroy Quet , Jul 02 2008

Discussion

Wed Apr 09

10:15

OEIS Server: https://oeis.org/edit/global/2151

#5 by N. J. A. Sloane at Wed Feb 05 20:18:47 EST 2014

AUTHOR

_Leroy Quet _ Jul 02 2008

Discussion

Wed Feb 05

20:18

OEIS Server: https://oeis.org/edit/global/2118

#4 by Russ Cox at Fri Mar 30 17:29:55 EDT 2012

EXTENSIONS

Extended by _Ray Chandler (rayjchandler(AT)sbcglobal.net), _, Jun 25 2009

Discussion

Fri Mar 30

17:29

OEIS Server: https://oeis.org/edit/global/154