

A070544


Number of squarefree numbers s such that n<s<2n.


0



0, 1, 1, 3, 2, 3, 3, 5, 6, 6, 6, 8, 7, 7, 7, 9, 9, 11, 11, 13, 13, 14, 13, 15, 15, 15, 16, 17, 17, 18, 18, 19, 19, 20, 20, 22, 22, 22, 22, 24, 23, 24, 24, 26, 27, 27, 27, 29, 30, 30, 30, 32, 32, 34, 34, 36, 36, 37, 36, 38, 37, 38, 38, 39, 39, 40, 40, 41, 41, 42, 42, 44, 44, 44, 45
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OFFSET

1,4


COMMENTS

lim n > infinity a(n)/n=6/Pi^2


LINKS

Table of n, a(n) for n=1..75.


MATHEMATICA

Table[Count[Range[n+1, 2n1], _?SquareFreeQ], {n, 80}] (* Harvey P. Dale, Mar 23 2019 *)


PROG

(PARI) for(n=1, 100, print1(sum(i=n+1, 2*n1, issquarefree(i)), ", "))


CROSSREFS

Sequence in context: A181672 A125748 A058680 * A087713 A089319 A140396
Adjacent sequences: A070541 A070542 A070543 * A070545 A070546 A070547


KEYWORD

easy,nonn


AUTHOR

Benoit Cloitre, May 02 2002


STATUS

approved



