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A054395 Numbers n such that there are precisely 2 groups of order n. +0
6
4, 6, 9, 10, 14, 21, 22, 25, 26, 34, 38, 39, 45, 46, 49, 55, 57, 58, 62, 74, 82, 86, 93, 94, 99, 105, 106, 111, 118, 121, 122, 129, 134, 142, 146, 153, 155, 158, 165, 166, 169, 175, 178, 183, 194, 195, 201, 202, 203, 205, 206, 207, 214, 218, 219, 226, 231, 237 (list; graph; listen)
OFFSET

1,1

LINKS

H.-U. Besche, The Small Groups library

Gordon Royle, Numbers of Small Groups

FORMULA

Numbers of the form p^2 and p_1*p_2*...*p_k where for exactly one pair (i, j) p_i | p_j - 1.

CROSSREFS

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

Sequence in context: A078972 A115652 A084759 this_sequence A142863 A132435 A108631

Adjacent sequences: A054392 A054393 A054394 this_sequence A054396 A054397 A054398

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), May 21 2000

EXTENSIONS

More terms, formula from Christian G. Bower (bowerc(AT)usa.net), May 25 2000

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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