A129253 - OEIS

%I #4 Mar 30 2012 18:50:58

%S 0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,6,6,6,7,8,8,8,8,9,9,9,

%T 9,10,10,10,10,11,11,11,11,12,12,12,12,13,13,13,13,14,14,15,15,16,16,

%U 16,16,17,17,17,17,18,18,18,18,19,19,19,19,20,20,20,20,21,21,21,21,22,23

%N Number of numbers not greater than n having at least one divisor p^e with p<=e, p prime.

%C a(1) = 1, a(n+1) = if A129251(n+1)>0 then a(n-1)+1 else a(n-1).

%H R. Zumkeller, <a href="/A129253/b129253.txt">Table of n, a(n) for n = 1..10000</a>

%K nonn

%O 1,8

%A _Reinhard Zumkeller_, Apr 07 2007