This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 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-François Alcover, May 16 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

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