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A074693 a(1)=1, a(n)=a(n-1)+phi(a(n-1)). 3
1, 2, 3, 5, 9, 15, 23, 45, 69, 113, 225, 345, 521, 1041, 1733, 3465, 4905, 7497, 11529, 18009, 29097, 47817, 71577, 114777, 184761, 307881, 482841, 804573, 1212813, 1854333, 2993517, 4953069, 7752429, 12826269, 21376953, 34207353, 55027593 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = partial sums of A165931(n). [From Jaroslav Krizek, Sep 30 2009]

LINKS

T. D. Noe, Table of n, a(n) for n=1..300

FORMULA

1 < a(n+1)/a(n) <= 2 . Does limit a(n+1)/a(n) exist ?

MATHEMATICA

NestList[# + EulerPhi@ # &, 1, 36] (* Robert G. Wilson v, Mar 02 2011 *)

CROSSREFS

Sequence in context: A067798 A205536 A281704 * A147322 A143282 A323475

Adjacent sequences:  A074690 A074691 A074692 * A074694 A074695 A074696

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Sep 03 2002

STATUS

approved

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Last modified August 7 17:44 EDT 2020. Contains 336278 sequences. (Running on oeis4.)