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A130738 Greedy odd Egyptian fraction representation of 1 (without repeats). 0

%I #11 Jul 17 2013 20:20:46

%S 3,5,7,9,11,13,23,721,979007,661211444787,622321538786143185105739,

%T 511768271877666618502328764212401495966764795565,

%U 209525411280522638000804396401925664136495425904830384693383280180439963265695525939102230139815

%N Greedy odd Egyptian fraction representation of 1 (without repeats).

%C a(n) is the largest odd Egyptian fraction as yet unused, such that the sum of the Egyptian fractions so far does not exceed 1. The sum of a(n) is a greedy representation (greedy because each step bites off as much as possible) of 1, using only odd Egyptian fractions, all distinct.

%C Terms a(11)-a(13) were found by David Eppstein (see posting from Nov 09 1996), who says that he found them by applying EgyptOddGreedy[2/3,5] from his Egyptian fractions notebook.

%D Mohammad K. Azarian, Sylvester's Sequence and the Infinite Egyptian Fraction Decomposition of 1, Problem 958, College Mathematics Journal, Vol. 42, No. 4, September 2011, p. 330. Solution published in Vol. 43, No. 4, September 2012, pp. 340-342

%D R. K. Guy, Unsolved Problems Number Theory, Sect D11.

%H David Eppstein, <a href="http://www.ics.uci.edu/~eppstein/numth/egypt/">Egyptian fractions</a>

%H David Eppstein, <a href="http://www.ics.uci.edu/~eppstein/numth/egypt/odd-one.html">Egyptian fractions</a>, Discussion, Nov 09 1996.

%H <a href="/index/Ed#Egypt">Index entries for sequences related to Egyptian fractions</a>

%e E.g. a(8)=721 because 1/721 is the largest odd Egyptian fraction less than 1-1/a(1)-1/a(2)-1/a(3)-1/a(4)-1/a(5)-1/a(6)-1/a(7).

%e 1/3 + 1/5 + 1/7 + 1/9 + 1/11 + 1/13 + 1/23 + 1/721 + 1/979007 + 1/661211444787 + 1/622321538786143185105739 + 1/511768271877666618502328764212401495966764795565 + 1/209525411280522638000804396401925664136495425904830384693383280180439963265695525939102230139815 = 1.

%Y Cf. A002966, A169820.

%K nonn,fini,full

%O 1,1

%A _Jon Wild_, Jul 06 2007

%E Edited and a(11)-a(13) added by _N. J. A. Sloane_, May 29 2010, at the suggestion of Jan Szejko.

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Last modified April 16 13:41 EDT 2024. Contains 371713 sequences. (Running on oeis4.)