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Worst cases for Pierce expansions (denominators).
(Formerly M2471)
2

%I M2471 #30 Jan 27 2023 13:44:56

%S 1,3,5,11,11,19,35,47,53,95,103,179,251,299,503,743,1019,1319,1439,

%T 2939,3359,3959,5387,5387,5879,5879,17747,17747,23399,23399,23399,

%U 23399,23399,23399,93596,186479,186479,278387,442679,493919,493919,493919,830939,1371719,1371719,1371719,1371719,1371719,1371719

%N Worst cases for Pierce expansions (denominators).

%C See A006537 for numerators.

%C a(58) <= 58017959. - _Hiroaki Yamanouchi_, Aug 31 2014

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Hiroaki Yamanouchi, <a href="/A006538/b006538.txt">Table of n, a(n) for n = 1..57</a>

%H P. Erdős and Jeffrey Shallit, <a href="http://www.numdam.org/item?id=JTNB_1991__3_1_43_0">New bounds on the length of finite Pierce and Engel series</a>, Sem. Theor. Nombres Bordeaux (2) 3 (1991), no. 1, 43-53.

%H Vlado Kešelj, <a href="http://www.cs.uwaterloo.ca/research/tr/1996/21/cs-96-21.pdf">Length of finite Pierce series: theoretical analysis and numerical computations</a>, Dept. Computer Science, U Waterloo, CS-96-21, Sep 10 1996.

%H M. E. Mays, <a href="http://www.fq.math.ca/Scanned/25-3/mays.pdf">Iterating the division algorithm</a>, Fib. Quart., 25 (1987), 204-213.

%H J. O. Shallit, <a href="https://www.fq.math.ca/Scanned/24-1/shallit.pdf">Metric theory of Pierce expansions</a>, Fibonacci Quart. 24 (1986), pp. 22-40.

%H <a href="/index/El#Engel">Index entries for sequences related to Engel expansions</a>

%F Chase & Pandey prove that a(n) >> n^e for some e > 59/19 = 3.105..., improving on Kešelj, Erdős & Shallit, and Shallit. - _Charles R Greathouse IV_, Jan 14 2023

%o (PARI) P(a, b)=my(n); while(b, b=a%b; n++); n

%o A268058(n)=my(t=1); for(b=2, n-1, t=max(P(n, b), t)); t

%o a(n,startAt=1)=while(A268058(startAt) < n, startAt++); startAt \\ _Charles R Greathouse IV_, Jan 14 2023

%Y RECORDS transform of A268058.

%K nonn,frac

%O 1,2

%A _Jeffrey Shallit_, _N. J. A. Sloane_

%E Description corrected May 15 1995 and again Nov 07 2006

%E a(38)-a(49) (from Keselj report) added by _R. J. Mathar_, Jun 30 2008

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Last modified September 19 21:59 EDT 2024. Contains 376015 sequences. (Running on oeis4.)