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A054396 Numbers n such that there are precisely 4 groups of order n. 22
28, 30, 44, 63, 66, 70, 76, 92, 102, 117, 124, 130, 138, 154, 170, 172, 174, 182, 188, 190, 230, 236, 238, 246, 266, 268, 275, 279, 282, 284, 286, 290, 315, 316, 318, 322, 332, 354, 370, 374, 387, 412, 418, 426, 428, 430, 434, 442, 465, 470, 494, 495, 498 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Muniru A Asiru, Table of n, a(n) for n = 1..369

H. U. Besche, B. Eick and E. A. O'Brien, The Small Groups Library

Gordon Royle, Numbers of Small Groups

Index entries for sequences related to groups

FORMULA

Sequence is { k | A000001(k) = 4 }. - Muniru A Asiru, Nov 04 2017

EXAMPLE

For n = 28, the 4 groups of order 8 are C7 : C4, C28, D28, C14 x C2 and for n = 30 the 4 groups of order 30 are C5 x S3, C3 x D10, D30, C30 where C, D mean Cyclic, Dihedral groups of the stated order and S is the Symmetric group of the stated degree. The symbols x and : mean direct and semidirect products respectively. - Muniru A Asiru, Nov 04 2017

MATHEMATICA

Select[Range[500], FiniteGroupCount[#] == 4 &] (* Jean-Fran├žois Alcover, Dec 08 2017 *)

PROG

(GAP) A054396 := Filtered([1..2015], n -> NumberSmallGroups(n) = 4); # Muniru A Asiru, Nov 04 2017

CROSSREFS

Cf. A000001, A003277, A054395, A054397, A055561, A054396, A135850.

Sequence in context: A042622 A044977 A046466 * A083274 A067913 A116566

Adjacent sequences:  A054393 A054394 A054395 * A054397 A054398 A054399

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, May 21 2000

EXTENSIONS

More terms from Christian G. Bower, May 25 2000

STATUS

approved

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Last modified August 6 17:06 EDT 2020. Contains 336255 sequences. (Running on oeis4.)