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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).
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..36
FORMULA
Limit_{n->oo} a(n)/10^n = A229099. - Robert G. Wilson v, Aug 12 2014
a(n) = 10^n - A071172(n). - Amiram Eldar, Mar 10 2024
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: A366995 A191468 A203243 * A198970 A361539 A014850
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 March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)