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Search: id:A099001
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| A099001 |
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(Sum 1/k) (Product k), where both the sum and product are over those k where 1 <= k <= n/2 and GCD(k,n) = 1. |
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+0
1
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| 1, 1, 1, 3, 1, 11, 4, 14, 4, 274, 6, 1764, 23, 106, 176, 109584, 47, 1026576, 300, 6960, 1689, 120543840, 552, 26854848, 19524, 7962160, 34986, 283465647360, 1312, 4339163001600, 4098240, 164944640, 4098240, 13833580032, 133542
(list; graph; listen)
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OFFSET
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2,4
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EXAMPLE
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a(8) = (1 +1/3)*1*3 = 4 because 1 and 3 are those positive integers <= 8/2 and coprime to 8.
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MAPLE
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b:=proc(n) local B, k: B:={}: for k from 1 to n/2 do if gcd(k, n)=1 then B:=B union {k} else B:=B fi od end: a:=proc(n) add(1/b(n)[j], j=1..nops(b(n)))*product(b(n)[j], j=1..nops(b(n))) end: seq(a(n), n=2..40); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 22 2006
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CROSSREFS
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Cf. A056855.
Sequence in context: A119632 A134761 A120291 this_sequence A119947 A027446 A027516
Adjacent sequences: A098998 A098999 A099000 this_sequence A099002 A099003 A099004
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Nov 13 2004
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 22 2006
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