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 A046306 Numbers that are divisible by exactly 6 primes with multiplicity. 57
 64, 96, 144, 160, 216, 224, 240, 324, 336, 352, 360, 400, 416, 486, 504, 528, 540, 544, 560, 600, 608, 624, 729, 736, 756, 784, 792, 810, 816, 840, 880, 900, 912, 928, 936, 992, 1000, 1040, 1104, 1134, 1176, 1184, 1188, 1215, 1224, 1232, 1260, 1312, 1320 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also called 6-almost primes. Products of exactly 6 primes (not necessarily distinct). Any 6-almost prime can be represented in several ways as a product of two 3-almost primes A014612 and in several ways as a product of three semiprimes A001358. - Jonathan Vos Post, Dec 11 2004 LINKS T. D. Noe, 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 = 6. a(n) ~ 120n log n / (log log n)^5. - Charles R Greathouse IV, May 06 2013 a(n) = A078840(6,n). - R. J. Mathar, Jan 30 2019 MATHEMATICA Select[Range, Plus @@ Last /@ FactorInteger[ # ] == 6 &] (* Vladimir Joseph Stephan Orlovsky, Apr 23 2008 *) Select[Range, PrimeOmega[#]==6&] (* Harvey P. Dale, May 21 2012 *) PROG (PARI) is(n)=bigomega(n)==6 \\ Charles R Greathouse IV, Mar 21 2013 CROSSREFS Cf. A046305, A120047 (number of 6-almost primes <= 10^n). Cf. A101605, A101606. 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), this sequence (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), A069279 (r = 18), A069280 (r = 19), A069281 (r = 20). - Jason Kimberley, Oct 02 2011 Sequence in context: A046305 A114828 A036330 * A223086 A175163 A255990 Adjacent sequences:  A046303 A046304 A046305 * A046307 A046308 A046309 KEYWORD nonn AUTHOR Patrick De Geest, Jun 15 1998 STATUS approved

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Last modified October 16 06:26 EDT 2019. Contains 328050 sequences. (Running on oeis4.)