|
| |
|
|
A166063
|
|
23-rough numbers: positive integers that have no prime factors less than 23
|
|
7
| |
|
|
1, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Or, positive integers relatively prime to 9699690 = 2*3*5*7*11*13*17*19.
First composite term is 529 = 23^2.
|
|
|
LINKS
| Eric Weisstein's World of Mathematics, Rough Number
Index entries for sequences related to smooth numbers [From Michael Porter (michael_b_porter(AT)yahoo.com), Oct 10 2009]
|
|
|
EXAMPLE
| 667 = 23 * 29 is in the sequence since the two prime factors, 23 and 29, are not less than 23.
|
|
|
MATHEMATICA
| Select[Range[500], FactorInteger[#][[1, 1]]>22&] (* From Harvey P. Dale, Nov 22 2010 *)
|
|
|
PROG
| (PARI) isA166063(n) = gcd(n, 9699690)==1 [From Michael Porter (michael_b_porter(AT)yahoo.com), Oct 10 2009]
|
|
|
CROSSREFS
| For k-rough numbers with other values of k, see A000027 A005408 A007310 A007775 A008364 A008365 A008366 A166061 A166063 [From Michael Porter (michael_b_porter(AT)yahoo.com), Oct 10 2009]
Sequence in context: A127495 A060703 A061753 * A049483 A112681 A078500
Adjacent sequences: A166060 A166061 A166062 * A166064 A166065 A166066
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Michael Porter (michael_b_porter(AT)yahoo.com), Oct 05 2009
|
|
|
EXTENSIONS
| Additional terms provided provided by Harvey P. Dale, Nov 22 2010
|
| |
|
|
