A079631 - OEIS

%I #17 Nov 16 2018 07:50:16

%S 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,

%T 18,18,18,19,19,19,20,20,20,21,21,21,22,22,22,23,23,23,24,24,24,25,25,

%U 25,26,26,26,27,27,27,28,28,28,29,29,29,30,31,31,31,31,32,32,32,32,33,33

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

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

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

%H Hugo Pfoertner, <a href="/A079631/b079631.txt">Table of n, a(n) for n = 1..10000</a>

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

%e a(1000)=172

%t Accumulate[Boole[Table[IntegerQ[n/Floor[n^(1/3)]], {n, 1, 73}]]] (* _Geoffrey Critzer_, May 25 2013 *)

%Y Cf. A321667.

%K nonn

%O 1,2

%A _Benoit Cloitre_, Jan 30 2003