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A062771
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Order of automorphism group of the group C_n X C_2 (where C_n is the cyclic group with n elements).
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2
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1, 6, 2, 8, 4, 12, 6, 16, 6, 24, 10, 16, 12, 36, 8, 32, 16, 36, 18, 32, 12, 60, 22, 32, 20, 72, 18, 48, 28, 48, 30, 64, 20, 96, 24, 48, 36, 108, 24, 64, 40, 72, 42, 80, 24, 132, 46, 64, 42, 120, 32, 96, 52, 108, 40, 96, 36, 168, 58, 64, 60, 180, 36, 128, 48, 120, 66, 128, 44
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OFFSET
| 1,2
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COMMENTS
| Multiplicative with a(2) = 6, a(2^e) = 2^(e+1), e>1, a(p^e) = (p-1)*p^(e-1), p>2. Christian G. Bower (bowerc(AT)usa.net) May 18, 2005.
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FORMULA
| For odd n: a(n) = phi(n) (sequence A000010).
Conjecture: a(n) = 6*phi(n) if n mod 4 = 2 and a(n) = 4*phi(n) if n mod 4 = 0. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 20 2001
Conjecture confirmed - Christian G. Bower, May 20 2005
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CROSSREFS
| Sequence in context: A082577 A098686 A079718 * A071874 A011331 A155687
Adjacent sequences: A062768 A062769 A062770 * A062772 A062773 A062774
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KEYWORD
| nonn,mult
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AUTHOR
| Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 18 2001
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EXTENSIONS
| More terms from Christian G. Bower (bowerc(AT)usa.net), May 20 2005
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