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A053145 When cototient function (A051953) is iterated with initial value A002110(n), a(n) = number of iterations required to reach the stationary value=0. +0
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2, 4, 7, 11, 17, 19, 30, 31, 40, 42, 60, 64, 79, 76, 94, 124, 130, 124, 156, 172, 139, 191, 194, 220, 212, 211, 260, 268, 276, 299, 295, 320, 335, 328, 357, 366, 378 (list; graph; listen)
OFFSET

1,1

FORMULA

a(n) is smallest number such that Nest[A051953, A002110(n), a(n)]=0.

EXAMPLE

n=6, A002110(6)=30030; the corresponding iteration chain is: {30030,24270,17806,9238,4798,2400,1760,1120,736,384,256,128,64,32,16,8,4,2,1,0}. Its length is 20, so a(6)=20-1=19.

CROSSREFS

A002110, A051953.

Sequence in context: A146921 A153535 A116615 this_sequence A101978 A076273 A024455

Adjacent sequences: A053142 A053143 A053144 this_sequence A053146 A053147 A053148

KEYWORD

more,nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Feb 28 2000

EXTENSIONS

More terms from Thomas Baruchel (baruchel(AT)users.sourceforge.net), Oct 11 2003

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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