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 A138812 a(0)=1, a(n) = sum{k=0 to n-1} floor(n/a(k)). 1
 1, 1, 4, 6, 9, 11, 14, 16, 19, 22, 24, 27, 31, 33, 36, 38, 42, 44, 48, 51, 54, 56, 60, 62, 67, 69, 71, 75, 79, 81, 84, 87, 91, 95, 97, 99, 105, 107, 111, 113, 116, 118, 123, 125, 131, 134, 136, 138, 145, 147, 149, 152, 155, 157, 163, 166, 171, 174, 176, 178, 183, 185 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA Probably a(n) ~ sqrt(2) n log(n)^(1/2) as n -> oo. - Robert Israel, May 02 2008 From Andrew V. Sutherland, May 02 2008: (Start) This is supported by the following data: a( 2) = 4, a(n)/n=2.0000, a(n)/(n*sqrt(log(n)))=2.4022 a( 4)= 9, a(n)/n=2.2500, a(n)/(n*sqrt(log(n)))=1.9110 a( 8)= 19, a(n)/n=2.3750, a(n)/(n*sqrt(log(n)))=1.6470 a( 16)= 42, a(n)/n=2.6250, a(n)/(n*sqrt(log(n)))=1.5765 a( 32)= 91, a(n)/n=2.8438, a(n)/(n*sqrt(log(n)))=1.5275 a( 64)= 196, a(n)/n=3.0625, a(n)/(n*sqrt(log(n)))=1.5017 a( 128)= 421, a(n)/n=3.2891, a(n)/(n*sqrt(log(n)))=1.4932 a( 256)= 896, a(n)/n=3.5000, a(n)/(n*sqrt(log(n)))=1.4863 a( 512)= 1892, a(n)/n=3.6953, a(n)/(n*sqrt(log(n)))=1.4795 a( 1024)= 3979, a(n)/n=3.8857, a(n)/(n*sqrt(log(n)))=1.4759 a( 2048)= 8335, a(n)/n=4.0698, a(n)/(n*sqrt(log(n)))=1.4739 a( 4096)= 17386, a(n)/n=4.2446, a(n)/(n*sqrt(log(n)))=1.4718 a( 8192)= 36146, a(n)/n=4.4124, a(n)/(n*sqrt(log(n)))=1.4699 a( 16384)= 74931, a(n)/n=4.5734, a(n)/(n*sqrt(log(n)))=1.4681 a( 32768)= 154964, a(n)/n=4.7291, a(n)/(n*sqrt(log(n)))=1.4666 a( 65536)= 319818, a(n)/n=4.8800, a(n)/(n*sqrt(log(n)))=1.4654 a(131072)= 658761, a(n)/n=5.0259, a(n)/(n*sqrt(log(n)))=1.4641 (End) MAPLE a[0]:=1: for n to 65 do a[n]:=sum(floor(n/a[k]), k=0..n-1) end do: seq(a[n], n =0..65); # Emeric Deutsch, Apr 04 2008 MATHEMATICA a = {1}; Do[AppendTo[a, Sum[Floor[n/a[[k]]], {k, 1, n}]], {n, 1, 70}]; a (* Stefan Steinerberger, Apr 04 2008 *) CROSSREFS Cf. A138813. Sequence in context: A010387 A010411 A047209 * A332587 A003259 A020935 Adjacent sequences:  A138809 A138810 A138811 * A138813 A138814 A138815 KEYWORD nonn AUTHOR Leroy Quet, Mar 31 2008 EXTENSIONS More terms from Stefan Steinerberger and Emeric Deutsch, Apr 04 2008 STATUS approved

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Last modified April 21 23:52 EDT 2021. Contains 343156 sequences. (Running on oeis4.)