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A069277 16-almost primes (generalization of semiprimes). 27
65536, 98304, 147456, 163840, 221184, 229376, 245760, 331776, 344064, 360448, 368640, 409600, 425984, 497664, 516096, 540672, 552960, 557056, 573440, 614400, 622592, 638976, 746496, 753664, 774144, 802816, 811008, 829440, 835584, 860160 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Product of 16 not necessarily distinct primes.

Divisible by exactly 16 prime powers (not including 1).

Any 16-almost prime can be represented in several ways as a product of two 8-almost primes A046310; in several ways as a product of four 4-almost primes A014613; and in several ways as a product of eight semiprimes A001358. - Jonathan Vos Post, Dec 12 2004

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 = 16.

MATHEMATICA

Select[Range[300000], Plus @@ Last /@ FactorInteger[ # ] == 16 &] (* Vladimir Joseph Stephan Orlovsky, Apr 23 2008 *)

Select[Range[10^6], PrimeOmega[#]==16&] (* Harvey P. Dale, Jan 30 2015 *)

PROG

(PARI) k=16; start=2^k; finish=1000000; v=[] for(n=start, finish, if(bigomega(n)==k, v=concat(v, n))); v

CROSSREFS

Cf. A014610, A101637, A101638, 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), 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), this sequence (r = 16), A069278 (r = 17), A069279 (r = 18), A069280 (r = 19), A069281 (r = 20). - Jason Kimberley, Oct 02 2011

Sequence in context: A223602 A223695 A202939 * A202932 A258737 A255667

Adjacent sequences:  A069274 A069275 A069276 * A069278 A069279 A069280

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 13 2002

STATUS

approved

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Last modified December 11 03:07 EST 2016. Contains 279034 sequences.