A079631 Number of k less than or equal to n such that floor(k^(1/3)) divides k.

1, 2, 3, 4, 5, 6, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 29, 29, 29, 30, 31, 31, 31, 31, 32, 32, 32, 32, 33, 33

Offset

1,2

Comments

Concrete Mathematics Casino Problem - number of winners up to N.

References

R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. 2nd Edition. Addison-Wesley, Reading, MA, 1994. Section 3.2, p74-76.

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

Formula

a(n)=floor(n/floor(n^(1/3)))+1/2*floor(n^(1/3))^2+5/2*floor(n^(1/3))-3

Example

a(1000)=172

Mathematica

Accumulate[Boole[Table[IntegerQ[n/Floor[n^(1/3)]], {n, 1, 73}]]] (* Geoffrey Critzer, May 25 2013 *)

Crossrefs

Cf. A321667.

Sequence in context: A289411 A328307 A327708 * A347623 A269849 A228881

Adjacent sequences: A079628 A079629 A079630 * A079632 A079633 A079634

Keyword

nonn

Author

Benoit Cloitre, Jan 30 2003

Status

approved