A118260 - OEIS

A118260

Number of weakly carefree couples (a,b) with a,b<=n.

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

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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

Table of n, a(n) for n=1..52.

Pieter Moree, Counting carefree couples, arXiv:math/0510003 [math.NT], 2005-2014.

Eric Weisstein's World of Mathematics, Carefree Couple.

FORMULA