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A242493 a(n) is the number of not-sqrt-smooth numbers ("jagged" numbers) not exceeding n. This is the counting function of A064052. 1
0, 1, 2, 2, 3, 4, 5, 5, 5, 6, 7, 7, 8, 9, 10, 10, 11, 11, 12, 13, 14, 15, 16, 16, 16, 17, 17, 18, 19, 19, 20, 20, 21, 22, 23, 23, 24, 25, 26, 26, 27, 28, 29, 30, 30, 31, 32, 32, 32, 32, 33, 34, 35, 35, 36, 36, 37, 38, 39, 39, 40, 41, 41, 41, 42, 43, 44, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

This sequence is different from shifted A072490, after 22 terms.

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, chapter 2.21, p. 166.

LINKS

Table of n, a(n) for n=1..68.

MATHEMATICA

jaggedQ[n_] := jaggedQ[n] = (f = FactorInteger[n][[All, 1]]; s = Sqrt[n]; Count[f, p_ /; p > s] > 0); a[n_] := ( For[ cnt = 0; j = 2, j <= n, j++, If[jaggedQ[j], cnt++]]; cnt); Table[a[n], {n, 1, 100}]

CROSSREFS

Cf. A064052.

Sequence in context: A054633 A327982 A072490 * A261345 A243285 A085972

Adjacent sequences:  A242490 A242491 A242492 * A242494 A242495 A242496

KEYWORD

nonn

AUTHOR

Jean-Fran├žois Alcover, May 16 2014

STATUS

approved

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Last modified October 17 14:31 EDT 2019. Contains 328114 sequences. (Running on oeis4.)