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A142863 Semiprimes n (A001358) for which A000001(n) is 2. 1
4, 6, 9, 10, 14, 21, 22, 25, 26, 34, 38, 39, 46, 49, 55, 57, 58, 62, 74, 82, 86, 93, 94, 106, 111, 118, 121, 122, 129, 134, 142, 146, 155, 158, 166, 169, 178, 183, 194, 201, 202, 203, 205, 206, 214, 218, 219, 226, 237, 253, 254, 262, 274, 278, 289, 291, 298, 301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Semiprimes p^2 or pq with p<q and gcd(p,q-1)=p. - T. D. Noe, Oct 08 2008

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.

CROSSREFS

Cf. A000001, A001358.

Sequence in context: A193305 A084759 A054395 * A318990 A132435 A108631

Adjacent sequences: A142860 A142861 A142862 * A142864 A142865 A142866

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 30 09:39 EDT 2023. Contains 361609 sequences. (Running on oeis4.)