

A063035


Number of integers m <= 10^n that contain a square factor (i.e., belong to A013929).


4



3, 39, 392, 3917, 39206, 392074, 3920709, 39207306, 392072876, 3920729058, 39207289720, 392072897726, 3920728981706, 39207289814053, 392072898145897, 3920728981459595
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OFFSET

1,1


COMMENTS

Note that "containing a square factor" (A013929) is different from "squareful" (A001694).
Lim n>inf. a(n)/10^n = A229099.  Robert G. Wilson v, Aug 12 2014


LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..36


MATHEMATICA

f[n_] := Sum[MoebiusMu[i]Floor[n/i^2], {i, 2, Sqrt@ n}]; Table[ f[10^n], {n, 0, 14}]


PROG

(PARI) { default(realprecision, 50); for (n=1, 100, t=10^n  1; a=10^n  sum(k=1, sqrt(t), moebius(k)*floor(t/k^2)); write("b063035.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 16 2009


CROSSREFS

For the complementary counts see A053462 and A071172.
Sequence in context: A292294 A191468 A203243 * A198970 A014850 A228749
Adjacent sequences: A063032 A063033 A063034 * A063036 A063037 A063038


KEYWORD

nonn


AUTHOR

Robert G. Wilson v, Aug 02 2001


EXTENSIONS

More terms from Harry J. Smith, Aug 16 2009
Edited (with a more precise definition and a new value for a(1)) by N. J. A. Sloane, Aug 06 2012. As a result of this change, the programs probably now give the wrong value for a(1). The source of the trouble was the ambiguous meaning of squareful  the official definition of squareful is A001694.


STATUS

approved



