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A039783
phi(n) is equal to the product of the dual prime-power components of n-1 (i.e., A008477(n-1)).
0
5, 17, 51, 73, 109, 433, 17408, 21601, 121501, 1350001, 3294173, 9376762501
OFFSET
1,1
COMMENTS
a(13) > 3*10^10. - Donovan Johnson
EXAMPLE
phi(17408) = 8192, 17407 = 13^2*103^1, (2^13)*(1^103) = 8192.
CROSSREFS
Sequence in context: A196310 A196283 A196333 * A374185 A103685 A116521
KEYWORD
nonn
EXTENSIONS
More terms from Naohiro Nomoto, Jun 24 2001
a(12) from Donovan Johnson, Nov 14 2010
STATUS
approved