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A129139
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a(n) = number of positive integers which are coprime to n and are <= d(n), where d(n) = A000005(n).
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1
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1, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 3, 2, 2, 2, 3, 3, 2, 4, 3, 2, 2, 3, 3, 2, 2, 2, 3, 3, 2, 2, 3, 3, 2, 3, 3, 2, 3, 4, 3, 3, 2, 2, 3, 2, 2, 4, 4, 4, 3, 2, 3, 3, 2, 2, 4, 2, 2, 3, 3, 4, 3, 2, 4, 4, 2, 2, 3, 4, 2, 3, 4, 2, 3, 4, 3, 3, 2, 4, 4, 2, 3, 4, 4, 2, 3, 2, 4, 4
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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EXAMPLE
| d(16) = 5. So a(16) is the number of integers coprime to 16 which are <= 5. There are 3 such integers: 1, 3, 5; so a(16) = 3.
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MAPLE
| with(numtheory): a:=proc(n) local ct, j: ct:=0: for j from 1 to tau(n) do if gcd(j, n)=1 then ct:=ct+1 else fi od: ct; end: seq(a(n), n=1..140); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 02 2007
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CROSSREFS
| Cf. A129138, A126131, A074919.
Sequence in context: A055666 A195061 A064130 * A032539 A122922 A046799
Adjacent sequences: A129136 A129137 A129138 * A129140 A129141 A129142
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Mar 30 2007
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 02 2007
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