|
| |
|
|
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 Orlovsky, Apr 23 2008
|
|
|
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 A016784 A016808
Adjacent sequences: A069274 A069275 A069276 * A069278 A069279 A069280
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Rick L. Shepherd, Mar 13 2002
|
|
|
STATUS
|
approved
|
| |
|
|
