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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 20 05:25 EDT 2019. Contains 326139 sequences. (Running on oeis4.)