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Search: id:A069274
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| A069274 |
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13-almost primes (generalization of semiprimes). |
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+0
8
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| 8192, 12288, 18432, 20480, 27648, 28672, 30720, 41472, 43008, 45056, 46080, 51200, 53248, 62208, 64512, 67584, 69120, 69632, 71680, 76800, 77824, 79872, 93312, 94208, 96768, 100352, 101376, 103680, 104448, 107520, 112640, 115200
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Divisible by exactly 13 primes (counted with multiplicity).
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LINKS
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D. W. Wilson, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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FORMULA
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Product p_i^e_i with Sum e_i = 13.
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MATHEMATICA
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Select[Range[30000], Plus @@ Last /@ FactorInteger[ # ] == 13 &] - Vladimir Orlovsky, Apr 23 2008
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PROGRAM
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(PARI) k=13; start=2^k; finish=130000; v=[] for(n=start, finish, if(bigomega(n)==k, v=concat(v, n))); v
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CROSSREFS
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Cf. A001358 (semiprimes), A069273 (12-almost primes), A069275 (14-almost primes) - A069281 (20-almost primes).
Sequence in context: A022195 A069388 A069414 this_sequence A017690 A010801 A138031
Adjacent sequences: A069271 A069272 A069273 this_sequence A069275 A069276 A069277
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KEYWORD
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nonn
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AUTHOR
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Rick L. Shepherd (rshepherd2(AT)hotmail.com), Mar 13 2002
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