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A116478
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a(1) = 1. a(n) = sum{1<=k<=n-1} floor(n/a(k)).
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0
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1, 2, 4, 7, 8, 10, 12, 16, 17, 20, 21, 25, 26, 29, 30, 35, 37, 39, 40, 45, 48, 50, 51, 56, 58, 61, 62, 66, 68, 72, 73, 78, 79, 82, 85, 89, 91, 93, 95, 102, 103, 107, 108, 111, 113, 115, 116, 123, 125, 130, 133, 137, 138, 140, 141, 147, 148, 152, 153, 160, 162, 165, 168
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| For n >= 2, a(n) also is sum{k=1 .. n} b(k), where b(k) is the number of terms of {a(j)} which divide k.
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EXAMPLE
| a(5)=8 because floor(5/1)+floor(5/2)+floor(5/4)+floor(5/7)=5+2+1+0=8.
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MAPLE
| a[1]:=1: for n from 2 to 70 do a[n]:=sum(floor(n/a[k]), k=1..n-1): od: seq(a[n], n=1..70); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 01 2006
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CROSSREFS
| Sequence in context: A056231 A131346 A047540 * A047236 A039581 A093701
Adjacent sequences: A116475 A116476 A116477 * A116479 A116480 A116481
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KEYWORD
| easy,nonn
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AUTHOR
| Leroy Quet Mar 18 2006
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 01 2006
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