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Search: id:A046310
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| A046310 |
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Numbers that are divisible by exactly 8 primes (counted with multiplicity). |
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22
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| 256, 384, 576, 640, 864, 896, 960, 1296, 1344, 1408, 1440, 1600, 1664, 1944, 2016, 2112, 2160, 2176, 2240, 2400, 2432, 2496, 2916, 2944, 3024, 3136, 3168, 3240, 3264, 3360, 3520, 3600, 3648, 3712, 3744, 3968, 4000, 4160, 4374, 4416, 4536, 4704, 4736
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Also called 8-almost primes. Products of exactly 8 primes (not necessarily distinct). Any 8-almost prime can be represented in several ways as a product of two 4-almost primes A014613, and in several ways as a product of four semiprimes A001358. - Jonathan Vos Post (jvospost2(AT)yahoo.com), Dec 11 2004
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
Eric Weisstein's World of Mathematics, Reference
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FORMULA
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Product p_i^e_i with Sum e_i = 8.
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MATHEMATICA
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Select[Range[1600], Plus @@ Last /@ FactorInteger[ # ] == 8 &] - Vladimir Orlovsky, Apr 23 2008
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CROSSREFS
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Cf. A046309, A120049 (number of 8-almost primes <= 10^n).
Cf. A014612, A014613, A001358, A101637, A101638, A101605, A101606.
Sequence in context: A046309 A036332 A114987 this_sequence A115176 A043336 A031465
Adjacent sequences: A046307 A046308 A046309 this_sequence A046311 A046312 A046313
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KEYWORD
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nonn
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AUTHOR
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Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
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