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Revision History for A163644

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A163644

Product of primes which do not exceed n and do not divide the swinging factorial n$ (A056040).
(history; published version)

#11 by Peter Luschny at Fri May 08 17:50:34 EDT 2020

STATUS

editing

approved

#10 by Peter Luschny at Fri May 08 17:50:29 EDT 2020

REFERENCES

Peter Luschny, "Divide, swing and conquer the factorial and the lcm{1,2,...,n}", preprint, April 2008.

LINKS

Peter Luschny, <a href="/A180000/a180000.pdf">Die schwingende Fakultät und Orbitalsysteme</a>, August 2011.

STATUS

approved

editing

#9 by Michel Marcus at Wed Aug 02 05:04:18 EDT 2017

STATUS

reviewed

approved

#8 by Joerg Arndt at Wed Aug 02 05:03:12 EDT 2017

STATUS

proposed

reviewed

#7 by G. C. Greubel at Tue Aug 01 12:25:54 EDT 2017

STATUS

editing

proposed

#6 by G. C. Greubel at Tue Aug 01 12:25:44 EDT 2017

LINKS

G. C. Greubel, <a href="/A163644/b163644.txt">Table of n, a(n) for n = 0..1000</a>

MATHEMATICA

A034386[x_] := Apply[Times, Table[Prime[w], {w, 1, PrimePi[x]}]];

sf[n_] := With[{f = Floor[n/2]}, Pochhammer[f + 1, n - f]/f!];

A163641[0] = 1; A163641[n_] := Times @@ FactorInteger[sf[n]][[All, 1]]; Join[{1}, Table[A034386[n]/A163641[n], {n, 1, 50}]] (* G. C. Greubel, Aug 01 2017 *)

STATUS

approved

editing

#5 by N. J. A. Sloane at Sun Sep 01 16:23:35 EDT 2013

STATUS

proposed

approved

#4 by Jon E. Schoenfield at Sun Sep 01 15:08:02 EDT 2013

STATUS

editing

proposed

#3 by Jon E. Schoenfield at Sun Sep 01 15:07:59 EDT 2013

EXAMPLE

a(20) = 105 because in the prime-factorisation factorization of 20$ the primes 3, 5 and 7 are missing and 3*5*7 = 105.

STATUS

approved

editing

#2 by Russ Cox at Fri Mar 30 17:27:12 EDT 2012

AUTHOR

_Peter Luschny (peter(AT)luschny.de), _, Aug 02 2009

Discussion

Fri Mar 30

17:27

OEIS Server: https://oeis.org/edit/global/141