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A142862 Semiprimes n (A001358) for which A000001(n) is 1. 1
15, 33, 35, 51, 65, 69, 77, 85, 87, 91, 95, 115, 119, 123, 133, 141, 143, 145, 159, 161, 177, 185, 187, 209, 213, 215, 217, 221, 235, 247, 249, 259, 265, 267, 287, 295, 299, 303, 319, 321, 323, 329, 335, 339, 341, 365, 371, 377, 391, 393, 395, 403, 407, 411 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Semiprimes pq with p<q and gcd(p,q-1)=1. - T. D. Noe, Oct 08 2008

REFERENCES

D. S. Dummit and R. M. Foote, Abstract Algebra, Wiley, 3rd Edition, 2003, page 135.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

John H. Conway, Heiko Dietrich and E. A. O'Brien, Counting groups: gnus, moas and other exotica.

MATHEMATICA

Select[Select[Range[1000], FactorInteger[#][[All, 2]] == {1, 1} &], !

Divisible[FactorInteger[#][[2, 1]] - 1, FactorInteger[#][[1, 1]]] &] (* Geoffrey Critzer, Nov 07 2015 *)

CROSSREFS

Cf. A050384, A003277. [Franklin T. Adams-Watters, Feb 27 2009]

Sequence in context: A338468 A337984 A050384 * A053343 A068081 A089967

Adjacent sequences: A142859 A142860 A142861 * A142863 A142864 A142865

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 03 2008

EXTENSIONS

More terms from R. J. Mathar, Oct 04 2008

STATUS

approved

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Last modified March 26 02:36 EDT 2023. Contains 361529 sequences. (Running on oeis4.)