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 A069274 13-almost primes (generalization of semiprimes). 26

%I

%S 8192,12288,18432,20480,27648,28672,30720,41472,43008,45056,46080,

%T 51200,53248,62208,64512,67584,69120,69632,71680,76800,77824,79872,

%U 93312,94208,96768,100352,101376,103680,104448,107520,112640,115200

%N 13-almost primes (generalization of semiprimes).

%C Product of 13 not necessarily distinct primes.

%C Divisible by exactly 13 prime powers (not including 1).

%H D. W. Wilson, <a href="/A069274/b069274.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 = 13.

%t Select[Range[30000], Plus @@ Last /@ FactorInteger[ # ] == 13 &] - Vladimir Orlovsky, Apr 23 2008

%o (PARI) k=13; start=2^k; finish=130000; v=[] for(n=start,finish, if(bigomega(n)==k,v=concat(v,n))); v

%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), this sequence (r = 13), A069275 (r = 14), A069276 (r = 15), A069277 (r = 16), A069278 (r = 17), A069279 (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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