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A053476
Smallest number m such that when A051953 is applied n times to m the result is neither a power of 2 nor 0.
0
9, 21, 42, 82, 130, 330, 450, 666, 1050, 1470, 1950, 2922, 4074, 5586, 7770, 11154, 15810, 22638, 30702, 42570, 53130, 68970, 107690, 159390, 206910, 289830, 395190, 610350, 823290, 1185570, 1522290, 2168250, 3011850, 4103490, 5364450
OFFSET
1,1
COMMENTS
An analog for A000005 is A049117.
FORMULA
Applying cototient-function A051953 n+1 times to a(n), a power of 2 or 0 appears; a(n) is the smallest with this property.
EXAMPLE
a(6)=330 and the iteration of A051953 applied to 330 gives sequence {330,250,150,110,70,46,24,16,8,4,2,1,0}. Six iterations result in the 6th term 24 which still is neither a power of 2 nor 0. For smaller numbers than 330 these 6 iterations yield a power of 2 or the fixed number 0.
CROSSREFS
Cf. A051953, see also its iterates.
Sequence in context: A110209 A184040 A242990 * A110680 A163205 A154862
KEYWORD
nonn
AUTHOR
Labos Elemer, Jan 14 2000
EXTENSIONS
More terms from Jud McCranie, Jan 14 2000
STATUS
approved