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A276733 Composite numbers n such that 2^lpf(n) == 2 (mod n), where lpf(n) = A020639(n). 1
341, 1247, 1387, 2047, 2701, 3277, 3683, 4033, 4369, 4681, 5461, 5963, 7957, 8321, 9017, 9211, 10261, 13747, 14351, 14491, 15709, 17593, 18721, 19951, 20191, 23377, 24929, 25351, 29041, 31417, 31609, 31621, 33227, 35333, 37901, 42799, 45761, 46513, 49141, 49601, 49981 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Super-Poulet numbers A050217 is a subsequence.
From Robert Israel, Sep 16 2016: (Start)
If p is a Wieferich prime (A001220), p^2 is in this sequence.
If p is a non-Wieferich prime, there are terms of the sequence divisible by p iff p < A006530(2^p-2). Is the latter true for all primes p except 2,3,5,7 and 13? (End)
LINKS
MAPLE
filter:= n -> not isprime(n) and 2 &^ min(numtheory:-factorset(n)) - 2 mod n = 0:
select(filter, [seq(i, i=3..100000, 2)]); # Robert Israel, Sep 16 2016
PROG
(PARI) lista(nn) = forcomposite(n=2, nn, if (Mod(2, n)^factor(n)[1, 1] == Mod(2, n), print1(n, ", ")); ); \\ Michel Marcus, Sep 16 2016
CROSSREFS
Sequence in context: A348258 A068216 A038473 * A050217 A214305 A086837
KEYWORD
nonn
AUTHOR
Thomas Ordowski, Sep 16 2016
EXTENSIONS
More terms from Michel Marcus, Sep 16 2016
STATUS
approved

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Last modified April 23 06:04 EDT 2024. Contains 371906 sequences. (Running on oeis4.)