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A046668 Numbers n such that partition function p(n) divides n!. 0
1, 2, 3, 7, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 24, 28, 32, 33, 39 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The symmetric group has p(n) conjugacy classes and order n! The sequence arose in a search for groups G which satisfy Pr(G)=k(G)/|G|=1/t, for integer t, where G has k(G) conjugacy classes.

The next term, if it exists, is > 30000. - Emeric Deutsch, Feb 26 2005

REFERENCES

Commutativity and Generalizations in Finite Groups; Aine NiShe, Ph.D. thesis in preparation.

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

a(1)=1, since p(1)=1 and 1 divides 1=1!; a(4)=7 because p(7)=15 and 15 divides 7!=5040.

MAPLE

with(combinat): p:=proc(n) if type(n!/numbpart(n), integer)=true then n else fi end; seq(p(n), n=1..30000); # Emeric Deutsch

MATHEMATICA

Do[ If[ Mod[n!, PartitionsP[n]] == 0, Print[n]], {n, 10000}] (* Robert G. Wilson v, Nov 23 2004 *)

Select[Range[40], Divisible[#!, PartitionsP[#]]&] (* Harvey P. Dale, Jan 30 2015 *)

PROG

(MAGMA) [ n : n in [1..40] | Factorial(n) mod NumberOfPartitions(n) eq 0 ]; // from Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006

CROSSREFS

Sequence in context: A114056 A168222 A140221 * A047533 A060525 A152863

Adjacent sequences:  A046665 A046666 A046667 * A046669 A046670 A046671

KEYWORD

nonn,nice

AUTHOR

Des MacHale

STATUS

approved

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Last modified December 16 01:36 EST 2017. Contains 296063 sequences.