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A229494
Lucky numbers generated from noncomposite numbers.
0
1, 3, 13, 19, 37, 43, 61, 71, 89, 101, 113, 131, 163, 181, 193, 223, 229, 251, 281, 293, 317, 337, 359, 397, 409, 433, 443, 463, 479, 503, 521, 557, 569, 593, 601, 641, 701, 719, 743, 757, 787, 809, 839, 863, 911, 929, 953, 971, 997
OFFSET
1,2
COMMENTS
Result of application of "Ulam's sieve" (used to produce the lucky numbers A000959) to the noncomposite numbers A008578 instead of the naturals A000027.
The "Lucky numbers generated from primes", cf. A059987 = (2, 5, 11, 17, ...), form a disjoint subset, because they are a subset of the odd-indexed primes, while the present sequence is the union of {1} and a subset of the even-indexed primes. - M. F. Hasler, Sep 24 2013
EXAMPLE
Start with noncomposite numbers A008578 = (1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, ...). Delete every 2nd number to get (1, 3, 7, 13, 19, 29, 37, ...). Since the next larger remaining number is 3, delete every 3rd term to get (1, 3, 13, 19, 37, ...). Then delete every 13th term, and so on.
PROG
(PARI) list_A229494(N=200)={my(v=concat(1, primes(N)), i=1); until(v[i++]>#v, v=vecextract(v, 2^#v-1-sum(j=1, #v\v[i+(i<2)], 2^(v[i+(i<2)]*j-1)))); v}
CROSSREFS
Sequence in context: A023215 A185069 A023239 * A211438 A018621 A236940
KEYWORD
nonn
AUTHOR
STATUS
approved