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%I #28 Jan 31 2017 12:29:50
%S 262144,393216,589824,655360,884736,917504,983040,1327104,1376256,
%T 1441792,1474560,1638400,1703936,1990656,2064384,2162688,2211840,
%U 2228224,2293760,2457600,2490368,2555904,2985984,3014656,3096576
%N Products of exactly 18 primes (generalization of semiprimes).
%C Product of 18 not necessarily distinct primes.
%C Divisible by exactly 18 prime powers (not including 1).
%H D. W. Wilson, <a href="/A069279/b069279.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/AlmostPrime.html">Almost Prime.</a>
%F Product p_i^e_i with Sum e_i = 18.
%t Select[Range[31*10^5],PrimeOmega[#]==18&] (* _Harvey P. Dale_, Apr 05 2015 *)
%o (PARI) k=18; start=2^k; finish=4000000; v=[] for(n=start,finish, if(bigomega(n)==k,v=concat(v,n))); v
%Y Cf. A101637, A101638, A101605, A101606.
%Y Sequences listing r-almost primes, that is, the n such that A001222(n) = r: A000040 (r = 1), A001358 (r = 2), A014612 (r = 3), A014613 (r = 4), A014614 (r = 5), A046306 (r = 6), A046308 (r = 7), A046310 (r = 8), A046312 (r = 9), A046314 (r = 10), A069272 (r = 11), A069273 (r = 12), A069274 (r = 13), A069275 (r = 14), A069276 (r = 15), A069277 (r = 16), A069278 (r = 17), this sequence (r = 18), A069280 (r = 19), A069281 (r = 20). - _Jason Kimberley_, Oct 02 2011
%K nonn
%O 1,1
%A _Rick L. Shepherd_, Mar 13 2002
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