|
|
A118260
|
|
Number of weakly carefree couples (a,b) with a,b<=n.
|
|
3
|
|
|
1, 3, 7, 11, 19, 23, 35, 43, 51, 59, 79, 87, 111, 123, 139, 153, 185, 197, 233, 247, 271, 291, 335, 351, 377, 401, 427, 445, 501, 517, 577, 603, 643, 675, 723, 745, 817, 853, 901, 929, 1009, 1033, 1117, 1151, 1187, 1231, 1323, 1353, 1405, 1439, 1503, 1541
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
(a, b) is a weakly carefree couple if gcd(a, b) = 1 and either a or b is squarefree (A005117). - Amiram Eldar, Mar 03 2021
|
|
REFERENCES
|
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.5.1 Carefree Couples, p. 110.
|
|
LINKS
|
|
|
FORMULA
|
a(n) ~ A118261 * n^2 + O(n*log(n)). (End)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|