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Search: id:A069273
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| A069273 |
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12-almost primes (generalization of semiprimes). |
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12
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| 4096, 6144, 9216, 10240, 13824, 14336, 15360, 20736, 21504, 22528, 23040, 25600, 26624, 31104, 32256, 33792, 34560, 34816, 35840, 38400, 38912, 39936, 46656, 47104, 48384, 50176, 50688, 51840, 52224, 53760, 56320, 57600, 58368, 59392
(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 12 primes (counted with multiplicity).
Any 12-almost prime can be represented in several ways as a product of two 6-almost primes A046306; in several ways as a product of three 4-almost primes A014613; in several ways as a product of four 3-almost primes A014612; and in several ways as a product of six semiprimes A001358. - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 11 2004
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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 = 12.
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MATHEMATICA
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Select[Range[20000], Plus @@ Last /@ FactorInteger[ # ] == 12 &] - Vladimir Orlovsky, Apr 23 2008
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PROGRAM
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(PARI) k=12; start=2^k; finish=70000; 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), A069272 (11-almost primes), A069274 (13-almost primes) - A069281 (20-almost primes).
Cf. A046306, A014612, A014613, A001358, A101637, A101638, A101605, A101606.
Sequence in context: A069413 A069439 A076154 this_sequence A043424 A138174 A016996
Adjacent sequences: A069270 A069271 A069272 this_sequence A069274 A069275 A069276
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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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