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 A069274 13-almost primes (generalization of semiprimes). 26
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Product of 13 not necessarily distinct primes. Divisible by exactly 13 prime powers (not including 1). LINKS D. W. Wilson, Table of n, a(n) for n = 1..10000 Eric Weisstein's World of Mathematics, Almost Prime. FORMULA Product p_i^e_i with Sum e_i = 13. MATHEMATICA Select[Range[30000], Plus @@ Last /@ FactorInteger[ # ] == 13 &] (* Vladimir Joseph Stephan Orlovsky, Apr 23 2008 *) PROG (PARI) k=13; start=2^k; finish=130000; v=[] for(n=start, finish, if(bigomega(n)==k, v=concat(v, n))); v CROSSREFS 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 Sequence in context: A069414 A289477 A222527 * A220585 A305756 A195661 Adjacent sequences:  A069271 A069272 A069273 * A069275 A069276 A069277 KEYWORD nonn AUTHOR Rick L. Shepherd, Mar 13 2002 STATUS approved

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Last modified November 19 17:19 EST 2018. Contains 317357 sequences. (Running on oeis4.)