

A057828


Number of perfect squares, k^2, where k^2 <= n and gcd(k,n) = 1.


3



1, 1, 1, 1, 2, 1, 2, 1, 2, 2, 3, 1, 3, 2, 2, 2, 4, 1, 4, 2, 3, 2, 4, 1, 4, 3, 4, 3, 5, 1, 5, 3, 4, 3, 4, 2, 6, 3, 4, 2, 6, 2, 6, 3, 3, 3, 6, 2, 6, 3, 5, 4, 7, 3, 6, 3, 5, 4, 7, 2, 7, 4, 4, 4, 7, 3, 8, 4, 6, 2, 8, 3, 8, 4, 5, 4, 7, 3, 8, 3, 6, 5, 9, 2, 8, 5, 6, 5, 9, 2, 8, 5, 6, 5, 8, 3, 9, 4, 6, 4, 10, 3, 10, 5
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OFFSET

1,5


COMMENTS

Number of square totatives of n, i.e., number of perfect squares less than n that are coprime to n.  Michael De Vlieger, Dec 11 2017


LINKS

Eric Weisstein's World of Mathematics, Totative.


EXAMPLE

Only 2 squares, 1 and 9, are <= 14 and relatively prime to 14. So a(14) = 2.


MATHEMATICA

Table[Count[Range[Sqrt@ n]^2, _?(CoprimeQ[#, n] &)], {n, 104}]


PROG

(Haskell)
a057828 x = length $ filter ((== 1) . (gcd x)) $
takeWhile (<= x) $ tail a000290_list


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



