|
Search: id:A069279
|
|
|
| A069279 |
|
18-almost primes (generalization of semiprimes). |
|
+0
11
|
|
| 262144, 393216, 589824, 655360, 884736, 917504, 983040, 1327104, 1376256, 1441792, 1474560, 1638400, 1703936, 1990656, 2064384, 2162688, 2211840, 2228224, 2293760, 2457600, 2490368, 2555904, 2985984, 3014656, 3096576
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Divisible by exactly 18 primes (counted with multiplicity).
Any 18-almost prime can be represented in several ways as a product of two 9-almost primes A046312; in several ways as a product of three 6-almost primes A046306; in several ways as a product of six 3-almost primes A014612; and in several ways as a product of nine semiprimes A001358. - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 12 2004
|
|
LINKS
|
D. W. Wilson, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
|
|
FORMULA
|
Product p_i^e_i with Sum e_i = 18.
|
|
PROGRAM
|
(PARI) k=18; start=2^k; finish=4000000; v=[] for(n=start, finish, if(bigomega(n)==k, v=concat(v, n))); v
|
|
CROSSREFS
|
Cf. A001358 (semiprimes), A069278 (17-almost primes), A069280 (19-almost primes), A069281 (20-almost primes).
Cf. A046312, A046306, A014612, A001358, A101637, A101638, A101605, A101606.
Sequence in context: A069393 A018867 A057445 this_sequence A068961 A016998 A017070
Adjacent sequences: A069276 A069277 A069278 this_sequence A069280 A069281 A069282
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Rick L. Shepherd (rshepherd2(AT)hotmail.com), Mar 13 2002
|
|
|
Search completed in 0.002 seconds
|
