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A110261 Number of distinct numbers that can be written as floor(n/i)+floor(n/j), 1<=i<=j<=n. 4

%I

%S 1,3,3,6,6,9,9,10,12,13,13,16,16,17,17,20,20,21,21,24,24,25,25,26,28,

%T 29,29,30,30,33,33,34,34,35,34,38,38,39,39,40,40,43,43,44,45,44,44,45,

%U 48,48,50,50,50,51,51,54,55,54,54,55,55,56,57,60,60,61,61,62,62,61,61,65

%N Number of distinct numbers that can be written as floor(n/i)+floor(n/j), 1<=i<=j<=n.

%C a(p) = a(p-1) for odd primes p;

%C the sequence is not monotonically increasing, see A110264 for numbers m with a(m)<a(m-1);

%C a(m)<a(A110262(n)) for m < A110262(n), a(A110262(n))=A110263(n);

%C A110265(n) = (smallest number <> floor(n/i)+floor(n/j), 1<=i<=j<=n).

%e a(10) = #{20,15,13,12,11,10,8,7,6,5,4,3,2} = 13:

%e 20=10/1+10/1, 15=10/1+10/2, 13=10/1+[10/3], 12=10/1+10/5,

%e 11=10/1+[10/6], 10=10/2+10/2, 8=10/2+[10/3], 7=10/2+10/5, 6=10/2+[10/6],

%e 5=[10/3]+10/5, 4=10/5+10/5, 3=10/5+[10/6] and 2=[10/6]+[10/6].

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Jul 18 2005

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Last modified October 7 12:03 EDT 2022. Contains 357271 sequences. (Running on oeis4.)