A053476 Smallest number m such that when A051953 is applied n times to m the result is neither a power of 2 nor 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.

Links

Table of n, a(n) for n=1..35.

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

Adjacent sequences: A053473 A053474 A053475 * A053477 A053478 A053479

Keyword

nonn

Author

Labos Elemer, Jan 14 2000

Extensions

More terms from Jud McCranie, Jan 14 2000

Status

approved